Issues with Mac Book Pro after migration

1. This procedure is a diagnostic test. It changes nothing, for better or worse, and therefore will not, in itself, solve the problem. But with the aid of the test results, the solution may take a few minutes, instead of hours or days.

Don't be put off by the complexity of these instructions. The process is much less complicated than the description. You do harder tasks with the computer all the time.

2. If you don't already have a current backup, back up all data before doing anything else. The backup is necessary on general principle, not because of anything in the test procedure. Backup is always a must, and when you're having any kind of trouble with the computer, you may be at higher than usual risk of losing data, whether you follow these instructions or not.

There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

3. Below are instructions to run a UNIX shell script, a type of program. As I wrote above, it changes nothing. It doesn't send or receive any data on the network. All it does is to generate a human-readable report on the state of the computer. That report goes nowhere unless you choose to share it. If you prefer, you can act on it yourself without disclosing the contents to me or anyone else.

You should be wondering whether you can believe me, and whether it's safe to run a program at the behest of a stranger. In general, no, it's not safe and I don't encourage it.

In this case, however, there are a couple of ways for you to decide whether the program is safe without having to trust me. First, you can read it. Unlike an application that you download and click to run, it's transparent, so anyone with the necessary skill can verify what it does.

You may not be able to understand the script yourself. But variations of it have been posted on this website thousands of times over a period of years. The site is hosted by Apple, which does not allow it to be used to distribute harmful software. Any one of the millions of registered users could have read the script and raised the alarm if it was harmful. Then I would not be here now and you would not be reading this message. See, for example, this discussion.

Nevertheless, if you can't satisfy yourself that these instructions are safe, don't follow them. Ask for other options.

4. Here's a summary of what you need to do, if you choose to proceed:

☞ Copy a line of text in this window to the Clipboard.

☞ Paste into the window of another application.

☞ Wait for the test to run. It usually takes a few minutes.

☞ Paste the results, which will have been copied automatically, back into a reply on this page.

The sequence is: copy, paste, wait, paste again. You don't need to copy a second time. Details follow.

5. Try to test under conditions that reproduce the problem, as far as possible. For example, if the computer is sometimes, but not always, slow, run the test during a slowdown.

You may have started up in "safe" mode. If the system is now in safe mode and works well enough in normal mode to run the test, restart as usual. If you can only test in safe mode, do that.

6. If you have more than one user, and the one affected by the problem is not an administrator, then please run the test twice: once while logged in as the affected user, and once as an administrator. The results may be different. The user that is created automatically on a new computer when you start it for the first time is an administrator. If you can't log in as an administrator, test as the affected user. Most personal Macs have only one user, and in that case this section doesn’t apply. Don't log in as root.

7. The script is a single long line, all of which must be selected. You can accomplish this easily by triple-clicking anywhere in the line. The whole line will highlight, though you may not see all of it in the browser window, and you can then copy it. If you try to select the line by dragging across the part you can see, you won't get all of it.

Triple-click anywhere in the line of text below on this page to select it:

PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/libexec;clear;cd;p=(1214 ' 0.5 0.25 10 1000 15 5120 1000 25000 1 1 0 100 ' 51 25600 4 10 25 5120 102400 1000 25 1000 80 40 500 300 85 25 20480 262144 20 2000 524288 );k=({Soft,Hard}ware Memory Diagnostics Power FireWire Thunderbolt USB Bluetooth SerialATA Extensions Applications Frameworks PrefPane Fonts Displays CFBundleIdentifier 'tsA|[ST]M[HL]' PlistBuddy{,' 2>&1'}' -c Print' 'Info\.plist' 'com\\.apple\\.' -\\t N\\/A 'AES|atr|udit|msa|dnse|ax|ensh|fami|FileS|fing|ft[pw]|gedC|kdu|etS|is\.|alk|ODSA|otp|htt|pcas|ps-lp|rexe|rlo|rsh|smb|snm|teln|upd-[aw]|uuc|vix|webf' OSBundle{Require,AllowUserLoa}d );f=('\n%s'{': ','\n\n'}'%s\n' '\nRAM details\n%s\n' %s\ %s '%s\n'"${k[22]}"'%s\n' {Privacy,Mode}': %s\n' '\n ...and %s more line(s)\n' 'RSSI: %s\nNoise: %s\nTx rate: %s\n' '\nContents of %s\n '"${k[22]}"'mod date: %s\n '"${k[22]}"'checksum: %s\n%s\n' '%d MB: %s\n' );b=(com.adobe.{AAM.Updater-1.0{,},AdobeCreativeCloud,CS{4,5}ServiceManager,fpsaud,SwitchBoard{,}} ${k[21]}{aelwriter,{AirPortBaseSt,SafariNotific}ationAgent,FolderActions.enabled,installer.osmessagetracing,mrt.uiagent,ReportCrash.Self,{rp,usb}muxd} com.citrixonline.GoToMeeting.G2MUpdate com.google.keystone.daemon com.microsoft.office.licensing.helper com.oracle.java.{Helper-Tool,JavaUpdateHelper{,}} org.macosforge.xquartz.{privileged_{,},}startx );c=(879294308 4071182229 461455494 3627668074 1083382502 1274181950 1855907737 2758863019 1848501757 464843899 2636415542 3694147963 1233118628 2456546649 2806998573 2778718105 842973933 2051385900 3301885676 891055588 695903914 1443423563 4136085286 523110921 2883943871 3873345487 );s=(' s/[0-9A-Za-z._]+@[0-9A-Za-z.]+\.[0-9A-Za-z]{2,4}/EMAIL/g;/faceb/s/(at\.)[^.]+/\1NAME/g;/\/Shared/!s/(\/Users\/)[^ /]+/\1USER/g;s/[-0-9A-Fa-f]{22,}/UUID/g;' ' s/^ +//;/de: S|[nst]:/p;' ' {sub(/^ +/,"")};/er:/;/y:/&&$2<'${p[4]} ' s/:$//;3,6d;/[my].+:/d;s/^ {4}//;H;${ g;s/\n$//;/s: (E[^m]|[^EO])|x([^08]|02[^F]|8[^0])/p;} ' ' 5h;6{ H;g;/P/!p;} ' ' ($1~/^Cy/&&$3>'${p[9]}')||($1~/^Cond/&&$2!~/^N/) ' ' /:$/{ N;/:.+:/d;s/ *://;b0'$'\n'' };/^ *(V.+ [0N]|Man).+ /{ s/ 0x.... //;s/[()]//g;s/(.+: )(.+)/ (\2)/;H;};$b0'$'\n'' d;:0'$'\n'' x;s/\n\n//;/Apple[ ,]|Genesy|Intel|SMSC/d;s/\n.*//;/\)$/p;' ' s/^.*C/C/;H;${ g;/No th|pms/!p;} ' '/= [^GO]/p' '{$1=""};1' ' /Of/!{ s/^.+is |\.//g;p;} ' ' BEGIN { FS=":";if(system("sw_vers -productVersion|grep -q ^10\.1")) d="^'"${k[21]}"'launch(d\.peruser\.[0-9]+|ctl\.(Aqua|Background|System))$";} { if($2~/[1-9]/) { $2="status: "$2;printf("'"${f[4]}"'",$1,$2);} else if(!d||$1!~d) print $1;} ' ' { sub(/ :/,"");print|"tail -n'${p[10]}'";} ' ' NR==2&&$4<='${p[7]}' { print $4;} ' ' ($1~"wir"&&$2>'${p[22]}')||($1~"uts"&&$2>'${p[19]}') { print $1" "int($2);} ' '|grep DYLD' ' { q=$1;$1="";u=$NF;$NF="";gsub(/ +$/,"");print q":"$0":"u;} ' ' /^ {6}[^ ]/d;s/:$//;/([^ey]|[^n]e):/d;/e: Y/d;s/: Y.+//g;H;${ g;s/ \n (\n)/\1/g;s/\n +(M[^ ]+)[ -~]+/ (\1)/;s/\n$//;/( {8}[^ ].*){2,}/p;} ' 's:^:/:p;' ' !/ /{print};END{if(NR<'{${p[12]},${p[13]}}')printf("^'"${k[21]}"'.+")} ' '|uniq' ' 1;END { if(NR<'{${p[14]},${p[21]}}') printf("^/[Sp]|'${k[21]}'");} ' ' /\.(framew|lproj)|\):/d;/plist:|:.+(Mach|scrip)/s/:.+//p;' '&&echo On' '/\.(bundle|component|framework|kext|mdimporter|plugin|qlgenerator|saver|wdgt)$/p' '/\.dylib$/p' ' /Temp|emac/{next};/(etc|Preferences|Launch[AD].+)\// { sub(".","");print;} END { split("'"${b[*]}"'",b);split("'"${c[*]}"'",c);for(i in b) print b[i]".plist\t"c[i];} ' ' /^\/(Ap|Dev|Inc|Prev)/d;/((iTu|ok).+dle|\.(component|mailbundle|mdimporter|plugin|qlgenerator|saver|wdgt))$/p;' ' $1 { gsub(/[()"]/,"",$3);if($2!="="||!$3) $3="N/A";print $3;} ' ' /^\// { sub("/dev/","",$1);printf("%s: %s\n",$1,$9);} ' '>&-||echo No' '{print $3"\t"$1}' 's/\'$'\t''.+//p' 's/1/On/p' '/Prox.+: [^0]/p' '$2>'${p[2]}'{$2=$2-1;print}' ' BEGIN { M1='${p[16]}';M2='${p[18]}';M3='${p[8]}';M4='${p[3]}';} !/^A/{next};/%/ { getline;if($5<M1) o["CPU"]="CPU: user "$2"%, system "$4"%";next;} $2~/^disk/&&$4>M2 { o[$2]=$2": "$3" ops/s, "$4" blocks/s";next;} $2~/^en[0-9]/ { if(o[$2]) { e=$3+$4+$5+$6;if(e) o[$2]=o[$2]"; errors "e"/s";next;};if($4>M3||$6>M4) o[$2]=$2": in "int($4/1024)", out "int($6/1024)" (KiB/s)";} END { for(i in o) print o[i];} ' ' /r\[0\] /&&$NF!~/^1(0|72\.(1[6-9]|2[0-9]|3[0-1])|92\.168)\./ { print $NF;exit;} ' ' !/^T/ { printf "(static)";exit;} ' '/apsd|BKAg|OpenD/!s/:.+//p' ' (/k:/&& $3!~/(255\.){3}0/)||(/v6:/&&$2!~/A/) ' ' $1=="op" {m=$3};$1~"lN" {N=$2};$1~"lR" {S=$2};$1~"Tx" {T=$2};$1~/^st/ {s=$2};$1~"li"&&$3!~"wpa2" {printf("'"${f[5]}"'",toupper($3))};END { if(S*N*T&&(S-N<'${p[5]}'||T<'${p[20]}')) printf("'"${f[8]}"'",S,N,T);if(s~/^r/&&m!~/^st/) printf("'"${f[6]}"'",m);} ' ' BEGIN { FS=":";} { n=split($3,a,".");sub(/_2[01].+/,"",$3);print $2" "$3" "a[n]$1;} ' ' BEGIN { split("'"${p[1]}"'",m);FS=":";} $2<=m[$1]{next} $1<9 { o[$1]=o[$1]"\n "$3" (UID "$4"): "$2;} $1==9&&$5!~"^/dev" { o[$1]=o[$1]"\n "$3" (UID "$4") => "$5" (status "$6"): "$2;} $1==10&&$5 { p="ps -c -ocomm -p"$5"|sed 1d";p|getline n;close(p);if(n) $5=n;o[$1]=o[$1]"\n "$5" => "$3" UID ("$4"): "$2;} $1~/1[12]/ { o[$1]=o[$1]"\n "$3" (UID "$4", error "$5"): "$2;} END { u1="Mb/s";u2="per sec";u3="ms/s";u4="KiB/s";u5="%";u6="total";u7="MB";u8="ports";u[1]=u1;u[2]=u1;u[3]=u3;u[4]=u4;u[5]=u5;u[6]=u6;u[7]=u7;u[8]=u8;u[9]=u2;u[10]=u2;u[11]=u2;u[12]=u2;l[1]="Net in";l[2]="Net out";l[3]="I/O wait time";l[4]="I/O requests";l[5]="CPU usage";l[6]="Open files";l[7]="Memory";l[8]="Mach ports";l[9]="File opens";l[10]="Forks";l[11]="Failed forks";l[12]="System errors";for(i in o) print "\n"l[i]" ("u[i]")\n"o[i];} ' ' END{if($3~/[0-9]/)print$3} ' ' BEGIN { L='${p[17]}';} !/^[[:space:]]*(#.*)?$/ { l++;if(l<=L) f=f"\n "$0;} END { F=FILENAME;if(!F) exit;if(!f) f="\n [N/A]";"cksum "F|getline C;split(C, A);C=A[1];"stat -f%Sm "F|getline D;"file -b "F|getline T;if(T~/^Apple b/) { f="";l=0;while("'"${k[18]}"' "F|getline g) { l++;if(l<=L) f=f"\n "g;};};if(T!~/^(AS.+ (En.+ )?text(, with v.+)?$|(Bo|PO).+ sh.+ text ex|XM)/) F=F"\n '"${k[22]}"'"T;printf("'"${f[9]}"'",F,D,C,f);if(l>L) printf("'"${f[7]}"'",l-L);} ' ' s/^ ?n...://p;s/^ ?p...:/-'$'\t''/p;' 's/0/Off/p' 's/^.{52}(.+) <.+/\1/p' ' /id: N|te: Y/{i++} END{print i} ' ' /kext:/ { split($0,a,":");p=a[1];k[S]='${k[25]}';k[U]='${k[26]}';v[S]="Safe";v[U]="true";for(i in k) { s=system("'"${k[18]}"'\\ :"k[i]" \""p"\"/*/I*|grep -qw "v[i]);if(!s) a[1]=a[1]" "i;};if(!a[2]) a[2]="'"${k[23]}"'";printf("'"${f[4]}"'",a[1],a[2]);next;} !/^ *$/ { p="'"${k[19]}"'\\ :'"${k[16]}"' \""$0"\"/*/'${k[20]}'";p|getline b;close(p);if(b~/ /||b=="") b="'"${k[23]}"'";printf("'"${f[4]}"'",$0,b);} ' '/ en/!s/\.//p' ' NR>=13 { gsub(/[^0-9]/,"",$1);print;} ' ' $10~/\(L/&&$9!~"localhost" { sub(/.+:/,"",$9);print $1": "$9|"sort|uniq";} ' '/^ +r/s/.+"(.+)".+/\1/p' 's/(.+\.wdgt)\/(Contents\/)?'${k[20]}'$/\1/p' 's/^.+\/(.+)\.wdgt$/\1/p' ' /l: /{ /DVD/d;s/.+: //;b0'$'\n'' };/s: /{ /V/d;s/^ */- 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/{\\.{kext,xpc,'(appex|pluginkit)'}'\/(Contents\/)?'Info,'Launch[AD].+'}'\.plist$/p' 's/([-+.?])/\\\1/g;p' 's/, /\'$'\n/g;p' ' BEGIN{FS=":"} { printf("'"${f[10]}"'",$1/1048576,$2);} ' ' /= D/&&$1!~/'{${k[24]},${k[17]}}'/ { getline d;if(d~"t") D=D"\n"$1;} END { print D;} ' ' NR>1&&$3!~/0x|\.([0-9]{3,}|[-0-9A-F]{36})$/ { print $3":"$2;} ' '|tail -n'${p[6]} ' $1>1 { $NF=$NF" x"$1;} /\*/ { if(!f) f="\n\t* Code injection";} { $1="";} 1;END { print f;} ' ' s/.+bus /Bus: /;s/,.+[(]/ /;s/,.+//p;' ' { $NF=$NF" Errors: "$1;$1="";} 1 ' ' 1s/^/\'$'\n''/;1s/:/ tree/;/^ +[MPSV].+:../d;s/:$//;p;' 's/,.+"//p' '|grep -q e:/' );c1=(system_profiler pmset\ -g nvram fdesetup find syslog df vm_stat sar ps crontab kextfind top pkgutil "${k[18]}\\" echo cksum kextstat launchctl smcDiagnose sysctl\ -n defaults\ read stat lsbom 'mdfind -onlyin /' env pluginkit scutil 'dtrace -q -x aggsortrev -n' profiles sed\ -En awk /S*/*/P*/*/*/C*/*/airport networksetup mdutil lsof test osascript\ -e netstat mdls route egrep 'dscl . -read' );c2=(${k[21]}loginwindow\ LoginHook ' /L*/P*/loginw*' "'tell app \"System Events\" to get properties of login items'" 'L*/Ca*/'${k[21]}'Saf*/E* -d 2 -name '${k[20]} '~ $TMPDIR.. \( -flags +sappnd,schg,uappnd,uchg -o ! -user $UID -o ! -perm -600 \)' -i '-nl -print' '-F \$Sender -k Level Nle 3 -k Facility CReq "apple\.'{'(bird|i?clou)','sharingd'}\" "-f'%N: %l' Desktop L*/Keyc*" therm sysload boot-args status " -F '\$Time \$(RefProc): \$Message' -k Sender Req 'fsev|kern|launchd' -k RefProc Rne 'Aq|WebK' -k Message Rne '08012|Goog|ksadm|probe|Roame|SMC:|smcD|sserti|suhel| VALI|ver-r|xpma' -k Message Req 'abn|bad |Beac|caug|corru|dead[^bl]|FAIL|fail|GPU |hfs: Ru|idle ex|inval|jnl:|last value [1-9]|lv_c|NVDA\(|pagin|pci pa|proc: t|Roamed|rror|SL|TCON|Throttli|tim(ed? ?|ing )o|WARN' " '-du -n DEV -n EDEV 1 10' 'acrx -o%cpu,comm,ruid' "' syscall::recvfrom:return {@a[execname,uid]=sum(arg0)} syscall::sendto:return {@b[execname,uid]=sum(arg0)} syscall::open*:entry {@c[execname,uid,copyinstr(arg0),errno]=count()} syscall::execve:return, syscall::posix_spawn:return {@d[execname,uid,ppid]=count()} syscall::fork:return, syscall::vfork:return, syscall::posix_spawn:return /arg0 < 0/ {@e[execname,uid,arg0]=count()} syscall:::return /errno != 0/ {@f[execname,uid,errno]=count()} io:::wait-start {self->t=timestamp} io:::wait-done /self->t/ { this->T=timestamp - self->t;@g[execname,uid]=sum(this->T);self->t=0;} io:::start {@h[execname,uid]=sum(args[0]->b_bcount)} tick-10sec { normalize(@a,2560000);normalize(@b,2560000);normalize(@c,10);normalize(@d,10);normalize(@e,10);normalize(@f,10);normalize(@g,10000000);normalize(@h,10240);printa(\"1:%@d:%s:%d\n\",@a);printa(\"2:%@d:%s:%d\n\",@b);printa(\"9:%@d:%s:%d:%s:%d\n\",@c);printa(\"10:%@d:%s:%d:%d\n\",@d);printa(\"11:%@d:%s:%d:%d\n\",@e);printa(\"12:%@d:%s:%d:%d\n\",@f);printa(\"3:%@d:%s:%d\n\",@g);printa(\"4:%@d:%s:%d\n\",@h);exit(0);} '" '-f -pfc /var/db/r*/'${k[21]}'*.{BS,Bas,Es,J,OSXU,Rem,up}*.bom' '{/,}L*/Lo*/Diag* -type f -regex .\*[cght] ! -name .?\* ! -name \*ag \( -exec grep -lq "^Thread c" {} \; -exec printf \* \; -o -true \) -execdir stat -f:%Sc:%N -t%F {} \;' '/S*/*/Ca*/*xpc*' '-L /{S*/,}L*/StartupItems -type f -exec file {} +' kMDItemContentTypeTree=${k[21]}{bundle,mach-o-dylib} :Label "/p*/e*/{aut*,{cron,fs}tab,hosts,{[lp],sy}*.conf,mach_i*/*,pam.d/*,ssh{,d}_config,*.local} {/p*,/usr/local}/e*/periodic/*/* /L*/P*{,/*}/com.a*.{Bo,sec*.ap}*t {/S*/,/,}L*/{Lau,Sec}*/*t .launchd.conf" list '-F "" -k Sender hidd -k Nle 3' /Library/Preferences/${k[21]}alf\ globalstate --proxy '-n get default' -I --dns -get{dnsservers,info} -P -m\ / '' -n1 '-R -ce -l1 -n5 -o'{'prt -stats prt','mem -stats mem'}',command,uid' -kl -l -s\ / '--regexp --files '${k[21]}'pkg.*' '+c0 -i4TCP:0-1023' ${k[21]}dashboard\ layer-gadgets '-d /L*/Mana*/$USER' '-app Safari WebKitDNSPrefetchingEnabled' '-Fcu +c0 -l' -m 'L*/{Con*/*/Data/L*/,}Pref* -type f -size 0c -name *.plist.???????' kern.memorystatus_vm_pressure_level '3>&1 >&- 2>&3' '-F \$Message -k Sender kernel -k Message CReq "'{'n Cause: -','(a und|I/O |jnl_io.+)err','USBF:'}'"' -name\ kMDItem${k[16]} -T\ hfs '-n get default' -listnetworkserviceorder :${k[16]} :CFBundleDisplayName $EUID {,'/{S*/,}'}'L*/{,Co*/*/*/L*/}{Cache,Log}s $TMPDIR../C -type f -size +'${p[11]}'M -exec stat -f'%z:%N' {} \;' \ /v*/d*/*/*l*d{,.*.$UID}/* '-app Safari UserStyleSheetEnabled' "-o ',\"name\":\"[^\"]+' L*/A*/Fi*/P*/*/a*.json" users/$USER\ HomeDirectory '{/,}L*/{Con,Pref}* -type f ! -size 0 -name *.plist -exec plutil -s {} \;' );N1=${#c2[@]};for j in {0..15};do c2[N1+j]=SP${k[j]}DataType;done;l=({Restricted\ ,Lock,Pro}files POST Battery {Safari,App,{Bad,Loaded}\ kernel,Firefox}\ extensions System\ load boot\ args FileVault\ {2,1} Log Free\ space VM Activity SMC Login\ hook 'I/O per process' 'High file counts' UID Daemons Agents XPC\ cache Startup\ items {Admin,Root}\ access Bundles {,Inserted\ }dylibs Stylesheet Font\ issues Firewall Proxies DNS TCP/IP Wi-Fi 'Elapsed time (sec)' {Root,User}\ crontab {Global,User}' login items' Spotlight Memory\ pressure Listeners Widgets Parental\ Controls Prefetching Nets Volumes {Continuity,I/O,iCloud,HID,HCI}\ errors {User,System}\ {caches/logs,overrides} Shutdown\ codes Heat Diagnostic\ reports Bad\ plists );N3=${#l[@]};for i in {0..8};do l[N3+i]=${k[5+i]};done;F() { local x="${s[$1]}";[[ "$x" =~ ^([\&\|\<\>]|$) ]]&&{ printf "$x";return;};:|${c1[30]} "$x" 2>&-;printf "%s \'%s\'" "|${c1[30+$?]}" "$x";};A0() { Q=6;v[2]=1;id -G|grep -qw 80;v[1]=$?;((v[1]))||{ Q=7;sudo -v;v[2]=$?;((v[2]))||Q=8;};v[3]=`date +%s`;date '+Start time: %T %D%n';printf '\n[Process started]\n\n'>&4;printf 'Revision: %s\n\n' ${p[0]};};A1() { local c="${c1[$1]} ${c2[$2]}";shift 2;c="$c ` while [[ "$1" ]];do F $1;shift;done`";((P2))&&{ c="sudo $c";P2=;};v=`eval "$c"`;[[ "$v" ]];};A2() { local c="${c1[$1]}";[[ "$c" =~ ^(awk|sed ) ]]&&c="$c '${s[$2]}'"||c="$c ${c2[$2]}";shift 2;local d=` while [[ "$1" ]];do F $1;shift;done`;((P2))&&{ c="sudo $c";P2=;};local a;v=` while read a;do eval "$c '$a' $d";done<<<"$v";`;[[ "$v" ]];};A3(){ v=$((`date +%s`-v[3]));};B1() { v=No;! ((v[1]))&&{ v=;P1=1;};};eval "`type -a B1|sed '1d;s/1/2/'`";B3(){ v[$1]="$v";};B4() { local i=$1;local j=$2;shift 2;local c="cat` while [[ "$1" ]];do F $1;shift;done`";v[j]=`eval "{ $c;}"<<<"${v[i]}"`;};B5(){ v[$1]="${v[$1]}"$'\n'"${v[$2]}";};B6() { v=` paste -d: <(printf "${v[$1]}") <(printf "${v[$2]}")|awk -F: ' {printf("'"${f[$3]}"'",$1,$2)} ' `;};B7(){ v=`egrep -v "${v[$1]}"<<<"$v"|sort`;};eval "`type -a B7|sed '1d;s/7/8/;s/-v //'`";C0() { [[ "$v" ]]&&sed -E "$s"<<<"$v";};C1() { [[ "$v" ]]&&printf "${f[$1]}" "${l[$2]}" "$v"|sed -E "$s";};C2() { v=`echo $v`;[[ "$v" != 0 ]]&&C1 0 $1;};C3() { B4 0 0 63&&C1 1 $1;};C4() { echo $'\t'"Part $((++P)) of $Q done at $((`date +%s`-v[3])) sec">&4;};C5() { sudo -k;pbcopy<<<"$o";printf '\n\tThe test results are on the Clipboard.\n\n\tPlease close this window.\n';exit 2>&-;};for i in 1 2;do eval D${i}0'(){ A'$i' $@;C0;};';for j in 2 3;do eval D$i$j'(){ x=$1;shift;A'$i' $@;C'$j' $x;};';done;done;trap C5 2;o=$({ A0;D10 0 N1+1 2;D10 0 $N1 1;B1;C2 27;B1&&! B2&&C2 28;D12 22 15 63;D10 0 N1+2 3;D10 0 N1+15 17;D13 3 0 N1+3 4;D13 4 0 N1+4 5;D13 N3+4 0 N1+9 59;for i in 0 1 2;do D13 N3+i 0 N1+5+i 6;done;D13 N3+3 0 N1+8 71;D13 62 1 10 7;D13 10 1 11 8;B2&&D13 18 19 53 67;D12 11 2 12 9;D12 12 3 13 10;D12 13 42 70 101 25;D12 15 6 36 13;D12 45 20 52 66;D13 16 7 37 14;D13 17 8 15 38;D10 9 16 16 77 45;C4;B2&&D10 35 49 61 75 76 78 45;B2&&{ D10 28 17 45;C4;};D10 12 40 54 16 79 45;D10 12 39 54 16 80 45;D13 31 25 37 15;B2&&D13 19 21 0;B2&&D13 40 10 42;B2&&D12 2 29 35 46;D12 44 34 43 53;D12 25 22 20 32;D12 33 0 N1+14 51;D12 34 21 28 35;D13 35 27 29 36;A1 40 59 81;B3 18;A1 33 60 82;B8 18;B4 0 19 83;A1 27 32 39&&{ B3 20;B4 19 0;A2 33 33 40;B3 21;B6 20 21 3;};C2 36;D13 50 38 5 68;B4 19 0;D23 37 33 34 42;B2&&D13 46 35 45 55;D13 38 32 31 43;B2&&D13 59 4 65 76 91;D13 63 4 19 44 75 95 96;B1&&{ D13 53 5 55 75 69&&D13 51 6 58 31;D13 56 5 56 97 75 98&&D10 0 N1+7 99;D12 55 5 27 84;D13 61 5 54 75 70;D13 14 5 14 12;C4;};A1 13 44 74 18;C4;B3 4;B4 4 0 85;A2 14 61 89;B4 0 5 19;A1 17 41 20;B7 5;C3 8;B4 4 0 88;A2 14 24 89;C4;B4 0 6 19;B4 4 0 86;A2 14 61 89;B4 0 7 19;B5 6 7;B4 6 6 73;B2&&{ A1 18 26 94;B7 6;B4 0 0 11;C3 23;};A1 18 26 94;B7 6;B4 0 0 11;C3 24;D13 60 14 66 92;D13 58 14 67 93;D13 26 4 21 24;D13 42 14 1 62;D13 43 37 2 90 48;D13 41 10 42;D12 48 36 47 25;A1 4 3 60&&{ B3 5;A2 14 61;B4 0 6 21;B4 5 0;A2 14 62;B4 0 0 21;B6 0 6 4;C3 5;};D13 9 41 69 100;D12 32 21 68 35;D12 49 21 48 49;B4 4 22 57;A1 21 46 56 74;B7 22;B4 0 0 58;C3 47;D13 54 5 7 75 69;D13 52 5 8 75 69;D13 57 4 64 76 91;D12 0 4 4 84;D12 1 4 51 84;D13 21 22 9 37;A1 23 18 28 89;B4 0 16 22;A1 16 25 33;B7 16;B4 0 0 34;D20 31 47;D13 64 4 71 41;C4;B4 4 12 26 89 23;for i in {0..3};do A1 0 N1+10+i 72;B7 12;B4 0 0 52;C3 N3+5+i;((i))||C4;done;A1 24 22 29;B7 12;B3 14;A2 39 57 30;B3 15;B6 14 15 4;C3 29;B4 4 13 27 89 65;A1 24 23;B7 13;C3 30;B4 4 0 87;A2 14 61 89 20;B4 0 16;A1 26 50 64;B7 16;C3 6;D13 7 11 6;A3;C2 39;C4;} 4>&2 2>/dev/null;);C5

Copy the selected text to the Clipboard by pressing the key combination command-C.

8. Launch the built-in Terminal application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Click anywhere in the Terminal window and paste by pressing command-V. The text you pasted should vanish immediately. If it doesn't, press the return key.

9. If you see an error message in the Terminal window such as "Syntax error" or "Event not found," enter

exec bash

and press return. Then paste the script again.

10. If you're logged in as an administrator, you'll be prompted for your login password. Nothing will be displayed when you type it. You will not see the usual dots in place of typed characters. Make sure caps lock is off. Type carefully and then press return. You may get a one-time warning to be careful. If you make three failed attempts to enter the password, the test will run anyway, but it will produce less information. In most cases, the difference is not important. If you don't know the password, or if you prefer not to enter it, just press return three times at the password prompt. Again, the script will still run.

If you're not logged in as an administrator, you won't be prompted for a password. The test will still run. It just won't do anything that requires administrator privileges.

11. The test may take a few minutes to run, depending on how many files you have and the speed of the computer. A computer that's abnormally slow may take longer to run the test. While it's running, a series of lines will appear in the Terminal window like this:

[Process started]

Part 1 of 8 done at … sec
…
Part 8 of 8 done at … sec

The results are on the Clipboard.

Please close this window.

[Process completed]

The intervals between parts won't be exactly equal, but they give a rough indication of progress. The total number of parts may be different from what's shown here.

Wait for the final message "Process completed" to appear. If you don't see it within about ten minutes, the test probably won't complete in a reasonable time. In that case, press the key combination control-C or command-period to stop it. Then go to the next step.

12. When the test is complete, or if you stopped it because it was taking too long, quit Terminal. The results will have been copied to the Clipboard automatically. They are not shown in the Terminal window. Please don't copy anything from there. All you have to do is start a reply to this comment and then paste by pressing command-V again.

At the top of the results, there will be a line that begins with the words "Start time." If you don't see that, but instead see a mass of gibberish, you didn't wait for the "Process completed" message to appear in the Terminal window. Please wait for it and try again.

If any private information, such as your name or email address, appears in the results, anonymize it before posting. Usually that won't be necessary.

13. When you post the results, you might see an error message on the web page: "You have included content in your post that is not permitted," or "You are not authorized to post." That's a bug in the forum software. Please post the test results on Pastebin, then post a link here to the page you created.

14. This is a public forum, and others may give you advice based on the results of the test. They speak only for themselves, and I may not agree with them.

______________________________________________________________

Copyright © 2014, 2015 by Linc Davis. As the sole author of this work, I reserve all rights to it except as provided in the Use Agreement for the Apple Support Communities website ("ASC"). Readers of ASC may copy it for their own personal use. Neither the whole nor any part may be redistributed.

The system is heavily modified by third-party software. Each such configuration is unique and unpredictable. I can only guess which of the many modifications may be contributing to the problem. As a start toward solving it, I suggest the following steps.

A

Some of your user files (not system files) have incorrect permissions or are locked. This procedure will unlock those files and reset their ownership, permissions, and access controls to the default. If you've intentionally set special values for those attributes, they will be reverted. In that case, either stop here, or be prepared to recreate the settings if necessary. Do so only after verifying that those settings didn't cause the problem. If none of this is meaningful to you, you don't need to worry about it, but you do need to follow the instructions below.

Back up all data before proceeding.

Step 1

If you have more than one user, and the one in question is not an administrator, then go to Step 2.

Enter the following command in the Terminal window in the same way as before (triple-click, copy, and paste):

sudo find ~ $TMPDIR.. -exec chflags -h nouchg,nouappnd,noschg,nosappnd {} + -exec chown -h $UID {} + -exec chmod +rw {} + -exec chmod -h -N {} + -type d -exec chmod -h +x {} + 2>&-

You'll be prompted for your login password, which won't be displayed when you type it. Type carefully and then press return. You may get a one-time warning to be careful. If you don’t have a login password, you’ll need to set one before you can run the command. If you see a message that your username "is not in the sudoers file," then you're not logged in as an administrator.

The command may take several minutes to run, depending on how many files you have. Wait for a new line ending in a dollar sign ($) to appear, then quit Terminal.

Step 2 (optional)

Take this step only if you have trouble with Step 1, if you prefer not to take it, or if it doesn't solve the problem.

Start up in Recovery mode. When the OS X Utilities screen appears, select

Utilities ▹ Terminal

from the menu bar. A Terminal window will open. In that window, type this:

resetp

Press the tab key. The partial command you typed will automatically be completed to this:

resetpassword

Press return. A Reset Password window will open. You’re not going to reset a password.

Select your startup volume ("Macintosh HD," unless you gave it a different name) if not already selected.

Select your username from the menu labeled Select the user account if not already selected.

Under Reset Home Directory Permissions and ACLs, click the Reset button.

Select

 ▹ Restart

from the menu bar.

B

Back up all data.

Run the following command in the same way as before. It moves to the Trash "semaphore" files that have not been cleaned up by the system and may be interfering with normal operation. The files are empty; they contain no data. There will be no output this time.

find L*/{Con*/*/Data/L*/,}Pref* -type f -size 0c -name *.plist.??????? -exec mv {} .Trash/ \; 2>&-

Log out or restart the computer and empty the Trash.

C

You recently activated FileVault. The startup volume is in the process of being encrypted. While that's going on, system performance will be reduced. Typically it takes a few hours. Follow the progress in the FileVault tab of the Security & Privacy preference pane. If it seems to be stuck, ask for instructions. Note that on a MacBook, encryption will only progress while the power adapter is connected to the computer and to wall power.

D

Open the iCloud pane in System Preferences. If the box marked iCloud Drive is checked, uncheck it and confirm. Your iCloud documents should be preserved on Apple's servers.

Test to see whether there's an improvement, then re-check the box and test again. It may take a noticeable amount of time for your iCloud Drive documents to resynchronize.

E

Uninstall the McAfee product by following the instructions on whichever of the pages linked below is applicable:

How to install or uninstall McAfee Internet Security for Mac

How to manually remove VirusScan for Mac 8.6.x using a removal script

How to uninstall and reinstall McAfee Agent 4.x on Macintosh computers

Note that if you have already tried to uninstall the software, you may have to reinstall it in order to finish the job. If you have a different version of the product, the procedure may be different.

F

"My Desktop" is crashing excessively. If that keeps happening after you take all the above steps, either remove it or refer to its developer (Oracle) for support.

G

Back up all data before proceeding.

Triple-click anywhere in the line below on this page to select it:

~/Library/Containers/com.apple.mail/Data/Library/Logs/Mail

Right-click or control-click the line and select

Services ▹ Open

from the contextual menu.* A folder should open. Quit the Mail application if it's running. Move the file with a name beginning in "stbeehive.oracle.com" to the Trash and empty. It's an excessively large log file.

*If you don't see the contextual menu item, copy the selected text to the Clipboard by pressing the key combination command-C. In the Finder, select

Go ▹ Go to Folder...

from the menu bar and paste into the box that opens by pressing command-V. You won't see what you pasted because a line break is included. Press return.

H

Uninstall or update "Seagate Drive Manager," which isn't working.

Any third-party software that doesn't install by drag-and-drop into the Applications folder, and uninstall by drag-and-drop to the Trash, is a system modification.

Whenever you remove system modifications, they must be removed completely, and the only way to do that is to use the uninstallation tool, if any, provided by the developers, or to follow their instructions. If the software has been incompletely removed, you may have to re-download or even reinstall it in order to finish the job.

I never install system modifications myself, and except as stated in this comment, I don't know how to uninstall them. You'll have to do your own research to find that information.

Here are some general guidelines to get you started. Suppose you want to remove something called “BrickMyMac” (a hypothetical example.) First, consult the product's Help menu, if there is one, for instructions. Finding none there, look on the developer's website, say www.brickmymac.com. (That may not be the actual name of the site; if necessary, search the Web for the product name.) If you don’t find anything on the website or in your search, contact the developer. While you're waiting for a response, download BrickMyMac.dmg and open it. There may be an application in there such as “Uninstall BrickMyMac.” If not, open “BrickMyMac.pkg” and look for an Uninstall button. The uninstaller might also be accessed by clicking the Customize button, if there is one.

Back up all data before making any changes.

You will generally have to restart the computer in order to complete an uninstallation. Until you do that, there may be no effect, or unpredictable effects.

If you can’t remove software in any other way, you’ll have to erase and install OS X. Never install any third-party software unless you're sure you know how to uninstall it; otherwise you may create problems that are very hard to solve.

Trying to remove complex system modifications by hunting for files by name often will not work and may make the problem worse. The same goes for "utilities" such as "AppCleaner" and the like that purport to remove software.

I

Storing many files on the Desktop may slow down the Finder, especially if the files have custom icons. Move most or all of the files to another subfolder of your home folder.

File Vault is stuck.

Back up all data before proceeding. There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

Start up in Recovery mode. When the OS X Utilities screen appears, select Disk Utility.

In the Disk Utility window, select the icon of the startup volume from the list on the left. It will be nested below another disk icon, usually with the same name. Click the Unlock button in the toolbar. When prompted, enter the login password of a user authorized to unlock the volume, or the alternate decryption key that was generated when you activated FileVault.

Then, from the menu bar, select

File ▹ Turn Off Encryption

Enter the password again.

You can then restart as usual, if the system is working. Decryption will be completed in the background. It may take several hours, and during that time performance will be reduced.

If you can't turn off encryption in Disk Utility because the menu item is grayed out, you'll have to erase the volume and then restore the data from a backup. Select the Erase tab, and then select

Mac OS Extended (Journaled)

from the Format menu.

You can then quit to be returned to the main Recovery screen. Follow these instructions if you back up with Time Machine. If you use other backup software, follow its developer's instructions.

Don't erase the volume unless you have at least two complete, independent backups. One is not enough to be safe.

McAffee is a recommendation of my work, Why do you suggest uninstall?

Mac users often ask whether they should install "anti-virus" (AV) software. The usual answer is "no." That answer is right, but it may give the wrong impression that there is no threat from what are loosely called "viruses." There is a threat, and you need to educate yourself about it.

1. This is a comment on what you should—and should not—do to protect yourself from malicious software ("malware") that circulates on the Internet and gets onto a computer as an unintended consequence of the user's actions.

It does not apply to software, such as keystroke loggers, that may be installed deliberately by an intruder who has hands-on access to the computer, or who has been able to take control of it remotely. That threat is in a different category, and there's no easy way to defend against it. AV software is not intended to, and does not, defend against such attacks.

The comment is long because the issue is complex. The key points are in sections 5, 6, and 10.

OS X now implements three layers of built-in protection specifically against malware, not counting runtime protections such as execute disable, sandboxing, system library randomization, and address space layout randomization that may also guard against other kinds of exploits.

2. All versions of OS X since 10.6.7 have been able to detect known Mac malware in downloaded files, and to block insecure web plugins. This feature is transparent to the user. Internally Apple calls it "XProtect."

The malware recognition database used by XProtect is automatically updated; however, you shouldn't rely on it, because the attackers are always at least a day ahead of the defenders.

The following caveats apply to XProtect:

☞ It can be bypassed by some third-party networking software, such as BitTorrent clients and Java applets.

☞ It only applies to software downloaded from the network. Software installed from a CD or other media is not checked.

As new versions of OS X are released, it's not clear whether Apple will indefinitely continue to maintain the XProtect database of older versions such as 10.6. The security of obsolete system versions may eventually be degraded. Security updates to the code of obsolete systems will stop being released at some point, and that may leave them open to other kinds of attack besides malware.

3. Starting with OS X 10.7.5, there has been a second layer of built-in malware protection, designated "Gatekeeper" by Apple. By default, applications and Installer packages downloaded from the network will only run if they're digitally signed by a developer with a certificate issued by Apple. Software certified in this way hasn't been checked for security by Apple unless it comes from the App Store, but you can be reasonably sure that it hasn't been modified by anyone other than the developer. His identity is known to Apple, so he could be held legally responsible if he distributed malware. That may not mean much if the developer lives in a country with a weak legal system (see below.)

Gatekeeper doesn't depend on a database of known malware. It has, however, the same limitations as XProtect, and in addition the following:

☞ It can easily be disabled or overridden by the user.

☞ A malware attacker could get control of a code-signing certificate under false pretenses, or could simply ignore the consequences of distributing codesigned malware.

☞ An App Store developer could find a way to bypass Apple's oversight, or the oversight could fail due to human error.

Apple has taken far too long to revoke the codesigning certificates of some known abusers, thereby diluting the value of Gatekeeper and the Developer ID program. Those lapses don't involve App Store products, however.

For the reasons given, App Store products, and—to a lesser extent—other applications recognized by Gatekeeper as signed, are safer than others, but they can't be considered absolutely safe. "Sandboxed" applications may prompt for access to private data, such as your contacts, or for access to the network. Think before granting that access. Sandbox security is based on user input. Never click through any request for authorization without thinking.

4. Starting with OS X 10.8.3, a third layer of protection has been added: a "Malware Removal Tool" (MRT). MRT runs automatically in the background when you update the OS. It checks for, and removes, malware that may have evaded the other protections via a Java exploit (see below.) MRT also runs when you install or update the Apple-supplied Java runtime (but not the Oracle runtime.) Like XProtect, MRT is effective against known threats, but not against unknown ones. It notifies you if it finds malware, but otherwise there's no user interface to MRT.

5. The built-in security features of OS X reduce the risk of malware attack, but they are not, and never will be, complete protection. Malware is a problem of human behavior, not machine behavior, and no technological fix alone is going to solve it. Trusting software to protect you will only make you more vulnerable.

The best defense is always going to be your own intelligence. With the possible exception of Java exploits, all known malware circulating on the Internet that affects a fully-updated installation of OS X 10.6 or later takes the form of so-called "Trojan horses," which can only have an effect if the victim is duped into running them. The threat therefore amounts to a battle of wits between you and Internet criminals. If you're better informed than they think you are, you'll win. That means, in practice, that you always stay within a safe harbor of computing practices. How do you know when you're leaving the safe harbor? Below are some warning signs of danger.

Software from an untrustworthy source

☞ Software with a corporate brand, such as Adobe Flash Player, doesn't come directly from the developer’s website. Do not trust an alert from any website to update Flash, or your browser, or any other software. A genuine alert that Flash is outdated and blocked is shown on this support page. Follow the instructions on the support page in that case. Otherwise, assume that the alert is fake and someone is trying to scam you into installing malware. If you see such alerts on more than one website, ask for instructions.

☞ Software of any kind is distributed via BitTorrent, or Usenet, or on a website that also distributes pirated music or movies.

☞ Rogue websites such as Softonic, Soft32, and CNET Download distribute free applications that have been packaged in a superfluous "installer."

☞ The software is advertised by means of spam or intrusive web ads. Any ad, on any site, that includes a direct link to a download should be ignored.

Software that is plainly illegal or does something illegal

☞ High-priced commercial software such as Photoshop is "cracked" or "free."

☞ An application helps you to infringe copyright, for instance by circumventing the copy protection on commercial software, or saving streamed media for reuse without permission. All "YouTube downloaders" are in this category, though not all are necessarily malicious.

Conditional or unsolicited offers from strangers

☞ A telephone caller or a web page tells you that you have a “virus” and offers to help you remove it. (Some reputable websites did legitimately warn visitors who were infected with the "DNSChanger" malware. That exception to this rule no longer applies.)

☞ A web site offers free content such as video or music, but to use it you must install a “codec,” “plug-in,” "player," "downloader," "extractor," or “certificate” that comes from that same site, or an unknown one.

☞ You win a prize in a contest you never entered.

☞ Someone on a message board such as this one is eager to help you, but only if you download an application of his choosing.

☞ A "FREE WI-FI !!!" network advertises itself in a public place such as an airport, but is not provided by the management.

☞ Anything online that you would expect to pay for is "free."

Unexpected events

☞ A file is downloaded automatically when you visit a web page, with no other action on your part. Delete any such file without opening it.

☞ You open what you think is a document and get an alert that it's "an application downloaded from the Internet." Click Cancel and delete the file. Even if you don't get the alert, you should still delete any file that isn't what you expected it to be.

☞ An application does something you don't expect, such as asking for permission to access your contacts, your location, or the Internet for no obvious reason.

☞ Software is attached to email that you didn't request, even if it comes (or seems to come) from someone you trust.

I don't say that leaving the safe harbor just once will necessarily result in disaster, but making a habit of it will weaken your defenses against malware attack. Any of the above scenarios should, at the very least, make you uncomfortable.

6. Java on the Web (not to be confused with JavaScript, to which it's not related, despite the similarity of the names) is a weak point in the security of any system. Java is, among other things, a platform for running complex applications in a web page, on the client. That was always a bad idea, and Java's developers have proven themselves incapable of implementing it without also creating a portal for malware to enter. Past Java exploits are the closest thing there has ever been to a Windows-style virus affecting OS X. Merely loading a page with malicious Java content could be harmful.

Fortunately, client-side Java on the Web is obsolete and mostly extinct. Only a few outmoded sites still use it. Try to hasten the process of extinction by avoiding those sites, if you have a choice. Forget about playing games or other non-essential uses of Java.

Java is not included in OS X 10.7 and later. Discrete Java installers are distributed by Apple and by Oracle (the developer of Java.) Don't use either one unless you need it. Most people don't. If Java is installed, disable it—not JavaScript—in your browsers.

Regardless of version, experience has shown that Java on the Web can't be trusted. If you must use a Java applet for a task on a specific site, enable Java only for that site in Safari. Never enable Java for a public website that carries third-party advertising. Use it only on well-known, login-protected, secure websites without ads. In Safari 6 or later, you'll see a padlock icon in the address bar when visiting a secure site.

Stay within the safe harbor, and you’ll be as safe from malware as you can practically be. The rest of this comment concerns what you should not do to protect yourself.

7. Never install any commercial AV or "Internet security" products for the Mac, as they are all worse than useless. If you need to be able to detect Windows malware in your files, use one of the free security apps in the Mac App Store—nothing else.

Why shouldn't you use commercial AV products?

☞ To recognize malware, the software depends on a database of known threats, which is always at least a day out of date. This technique is a proven failure, as a major AV software vendor has admitted. Most attacks are "zero-day"—that is, previously unknown. Recognition-based AV does not defend against such attacks, and the enterprise IT industry is coming to the realization that traditional AV software is worthless.

☞ Its design is predicated on the nonexistent threat that malware may be injected at any time, anywhere in the file system. Malware is downloaded from the network; it doesn't materialize from nowhere. In order to meet that nonexistent threat, commercial AV software modifies or duplicates low-level functions of the operating system, which is a waste of resources and a common cause of instability, bugs, and poor performance.

☞ By modifying the operating system, the software may also create weaknessesthat could be exploited by malware attackers.

☞ Most importantly, a false sense of security is dangerous.

8. An AV product from the App Store, such as "ClamXav," has the same drawback as the commercial suites of being always out of date, but it does not inject low-level code into the operating system. That doesn't mean it's entirely harmless. It may report email messages that have "phishing" links in the body, or Windows malware in attachments, as infected files, and offer to delete or move them. Doing so will corrupt the Mail database. The messages should be deleted from within the Mail application.

An AV app is not needed, and cannot be relied upon, for protection against OS X malware. It's useful, if at all, only for detecting Windows malware, and even for that use it's not really effective, because new Windows malware is emerging much faster than OS X malware.

Windows malware can't harm you directly (unless, of course, you use Windows.) Just don't pass it on to anyone else. A malicious attachment in email is usually easy to recognize by the name alone. An actual example:

London Terror Moovie.avi [124 spaces] Checked By Norton Antivirus.exe

You don't need software to tell you that's a Windows trojan. Software may be able to tell you which trojan it is, but who cares? In practice, there's no reason to use recognition software unless an organizational policy requires it. Windows malware is so widespread that you should assume it's in every email attachment until proven otherwise. Nevertheless, ClamXav or a similar product from the App Store may serve a purpose if it satisfies an ill-informed network administrator who says you must run some kind of AV application. It's free and it won't handicap the system.

The ClamXav developer won't try to "upsell" you to a paid version of the product. Other developers may do that. Don't be upsold. For one thing, you should not pay to protect Windows users from the consequences of their choice of computing platform. For another, a paid upgrade from a free app will probably have all the disadvantages mentioned in section 7.

9. It seems to be a common belief that the built-in Application Firewall acts as a barrier to infection, or prevents malware from functioning. It does neither. It blocks inbound connections to certain network services you're running, such as file sharing. It's disabled by default and you should leave it that way if you're behind a router on a private home or office network. Activate it only when you're on an untrusted network, for instance a public Wi-Fi hotspot, where you don't want to provide services. Disable any services you don't use in the Sharing preference pane. All are disabled by default.

10. As a Mac user, you don't have to live in fear that your computer may be infected every time you install software, read email, or visit a web page. But neither can you assume that you will always be safe from exploitation, no matter what you do. Navigating the Internet is like walking the streets of a big city. It can be as safe or as dangerous as you choose to make it. The greatest harm done by security software is precisely its selling point: it makes people feel safe. They may then feel safe enough to take risks from which the software doesn't protect them. Nothing can lessen the need for safe computing practices.