Kernel_task high CPU usage

This really work for my case..

After a frustrating all over googling to fix my problem what a relieve..

My Environment : MBP 2012, 13"

Symptom : sluggish and slow performance, I thought because of my upgrade to Sierra, but comparing performance with my older Macbook Air it seem not right. Watching my activity monitor turn out kernel_task that taking everything.

Kernel_Task taking up cpu and memory up to 300% cpu usage

After trying many suggestion from the forum this one fix my problem...

thanks guys..

The kernel is using excessive processor cycles. Below are some possible causes for the condition.

Throttling

When it gets high temperature readings from the hardware, or a low-voltage reading from the battery, the kernel may try to compensate by interrupting the processor(s) to slow them down and reduce power consumption. This condition can be due to:

☞ a buildup of dust on the logic board

☞ high ambient temperature

☞ a worn-out or faulty battery in a portable

☞ the malfunction of a cooling fan, a temperature sensor, a voltage sensor, or some other internal component

Note that if the problem is caused by a sensor, there may be no actual overheating or undervoltage.

If the computer is portable, test with and without the AC adapter connected. If kernel_task hogs the processor only on battery power, the fault is in the battery or the logic board. If it happens only on AC power, charging is causing the machine to heat up. That may be normal on some models. CPU usage should drop when charging is complete.

Apple Diagnostics or the Apple Hardware Test, though not very reliable, is sometimes able to detect a fault. For more thorough hardware testing, make a "Genius" appointment at an Apple Store, or go to another authorized service provider.

If nothing is wrong with the hardware, then whatever you can do to improve cooling may help.

Installed software

User-installed software that includes a device driver or other kernel code may thrash the kernel. That category includes virtualization software, such as Parallels and VMware, as well as most commercial "anti-virus" products. Some system-monitoring applications, such as "iStat," can also contribute to the problem. You can test for this possibility by completely disabling or removing the software according to the developer's instructions, or starting in safe mode. Note, however, that disabling a system modification without removing it or testing in safe mode may not be as easy as you think.

Corrupt NVRAM or SMC data

Sometimes the problem is cleared up by resetting the NVRAM or the SMC.

External display

Connecting an external LCD display to some MacBook Pro models while the lid is open may cause this issue. If applicable, test by closing the lid or disconnecting the display. You might get better results with a newer LED display.

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 merely by the seeming 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. All it does is to collect information about the state of the computer. That information goes nowhere unless you choose to share it. However, you should be cautious about running any kind of program (not just a shell script) at the behest of a stranger. If you have doubts, search this site for other discussions in which this procedure has been followed without any report of ill effects. If you can't satisfy yourself that the instructions are safe, don't follow them. Ask for other options.

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.

4. You may have started the computer in "safe" mode. Preferably, these steps should be taken in “normal” mode, under the conditions in which the problem is reproduced. 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.

5. 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.

6. 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=(Software Hardware Memory Diagnostics Power FireWire Thunderbolt USB Fonts SerialATA 4 1000 25 5120 KiB/s 1024 85 \\b%% 20480 1 MB/s 25000 ports ' com.clark.\* \*dropbox \*GoogleDr\* \*k.AutoCAD\* \*k.Maya\* vidinst\* ' DYLD_INSERT_LIBRARIES\ DYLD_LIBRARY_PATH -86 ` route -n get default|awk '/e:/{print $2}' ` 25 N\\/A down up 102400 25600 recvfrom sendto CFBundleIdentifier 25 25 25 1000 MB com.apple.AirPortBaseStationAgent 464843899 51 );N5=${#p[@]};p[N5]=` networksetup -listnetworkserviceorder|awk ' NR>1 { sub(/^\([0-9]+\) /,"");n=$0;getline;} $NF=="'${p[26]}')" { sub(/.$/,"",$NF);print n;exit;} ' `;f=('\n%s: %s\n' '\n%s\n\n%s\n' '\nRAM details\n%s\n' %s\ %s '%s\n-\t%s\n' );S0() { echo ' { q=$NF+0;$NF="";u=$(NF-1);$(NF-1)="";gsub(/^ +| +$/,"");if(q>='${p[$1]}') printf("%s (UID %s) is using %s '${p[$2]}'",$0,u,q);} ';};s=(' /^ *$|CSConfigDot/d;s/^ */ /;s/[-0-9A-Fa-f]{22,}/UUID/g;s/(ochat)\.[^.]+(\..+)/\1\2/;/Shared/!s/\/Users\/[^/]+/~/g ' ' s/^ +//;5p;6p;8p;12p;' ' {sub(/^ +/,"")};NR==6;NR==13&&$2<'${p[10]} ' 1s/://;3,6d;/[my].+:/d;s/^ {4}//;H;${ g;s/\n$//;/s: [^EO]|x([^08]|02[^F]|8[^0])/p;} ' ' 5h;6{ H;g;/P/!p;} ' ' ($1~/^Cy/&&$3>'${p[11]}')||($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[ ,]|Intel|SMSC/d;s/\n.*//;/\)$/p;' ' s/^.*C/C/;H;${ g;/No th|pms/!p;} ' '/= [^GO]/p' '{$1=""};1' ' /Of/!{ s/^.+is |\.//g;p;} ' ' $0&&!/ / { n++;print;} END { if(n<200) print "com.apple.";} ' ' $3~/[0-9]:[0-9]{2}$/ { gsub(/:[0-9:a-f]{14}/,"");} { print|"tail -n'${p[12]}'";} ' ' NR==2&&$4<='${p[13]}' { print $4;} ' ' END { $2/=256;if($2>='${p[15]}') print int($2) } ' ' NR!=13{next};{sub(/[+-]$/,"",$NF)};'"`S0 21 22`" 'NR!=2{next}'"`S0 37 17`" ' NR!=5||$8!~/[RW]/{next};{ $(NF-1)=$1;$NF=int($NF/10000000);for(i=1;i<=3;i++){$i="";$(NF-1-i)="";};};'"`S0 19 20`" 's:^:/:p' '/\.kext\/(Contents\/)?Info\.plist$/p' 's/^.{52}(.+) <.+/\1/p' ' /Launch[AD].+\.plist$/ { n++;print;} END { print "'${p[41]}'";if(n<200) print "/System/";} ' '/\.xpc\/(Contents\/)?Info\.plist$/p' ' NR>1&&!/0x|\.[0-9]+$|com\.apple\.launchctl\.(Aqua|Background|System)$|'${p[41]}'/ { print $3;} ' ' /\.(framew|lproj)|\):/d;/plist:|:.+(Mach|scrip)/s/:[^:]+//p ' '/root/p' ' !/\/Contents\/.+\/Contents|Applic|Autom|Frameworks/&&/Lib.+\/Info.plist$/ { n++;print;} END { if(n<1100) print "/System/";} ' '/^\/usr\/lib\/.+dylib$/p' ' /Temp|emac/ { next;} /(etc|Preferences|Launch[AD].+)\// { sub(".(/private)?","");n++;print;} END { print "'${p[41]}'.plist\t'${p[42]}'";if(n<500) print "Launch";} ' ' /\/(Contents\/.+\/Contents|Frameworks)\/|\.wdgt\/.+\.([bw]|plu)/d;p;' 's/\/(Contents\/)?Info.plist$//;p' ' { gsub("^| |\n","\\|\\|kMDItem'${p[35]}'=");sub("^...."," ") };1 ' p '{print $3"\t"$1}' 's/\'$'\t''.+//p' 's/1/On/p' '/Prox.+: [^0]/p' '$2>'${p[43]}'{$2=$2-1;print}' ' BEGIN { i="'${p[26]}'";M1='${p[16]}';M2='${p[18]}';M3='${p[31]}';M4='${p[32]}';} !/^A/ { next;} /%/ { getline;if($5<M1) a="user "$2"%, system "$4"%";} /disk0/&&$4>M2 { b=$3" ops/s, "$4" blocks/s";} $2==i { if(c) { d=$3+$4+$5+$6;next;};if($4>M3||$6>M4) c=int($4/1024)" in, "int($6/1024)" out";} END { if(a) print "CPU: "a;if(b) print "I/O: "b;if(c) print "Net: "c" (KiB/s)";if(d) print "Net errors: "d" packets/s";} ' ' /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~"lR"&&$2<='${p[25]}';$1~"li"&&$3!~"wpa2";' ' BEGIN { FS=":";} { n=split($3,a,".");sub(/_2[01].+/,"",$3);print $2" "$3" "a[n]" "$1;b=b$1;} END { if(b) print("\n\t* Code injection");} ' ' NR!=4{next} {$NF/=10240} '"`S0 27 14`" ' END { if($3~/[0-9]/)print$3;} ' ' BEGIN { L='${p[36]}';} !/^[[:space:]]*(#.*)?$/ { l++;if(l<=L) f=f"\n "$0;} END { F=FILENAME;if(!F) exit;if(!f) f="\n [N/A]";"file -b "F|getline T;if(T!~/^(AS.+ (En.+ )?text$|POSIX sh.+ text ex)/) F=F" ("T")";printf("\nContents of %s\n%s\n",F,f);if(l>L) printf("\n ...and %s more line(s)\n",l-L);} ' ' /^ +[NP].+ =/h;/^( +D.+[{]|[}])/{ g;s/.+= //p;};' 's/0/Off/p' ' END{print NR} ' ' /id: N|te: Y/{i++} END{print i} ' ' / / { print "'"${p[28]}"'";exit;};1;' '/ en/!s/\.//p' ' NR!=13{next};{sub(/[+-M]$/,"",$NF)};'"`S0 39 40`" ' $10~/\(L/&&$9!~"localhost" { sub(/.+:/,"",$9);print $1": "$9;} ' '/^ +r/s/.+"(.+)".+/\1/p' 's/(.+\.wdgt)\/(Contents\/)?Info\.plist$/\1/p' 's/^.+\/(.+)\.wdgt$/\1/p' ' /l: /{ /DVD/d;s/.+: //;b0'$'\n'' };/s: /{ /V/d;s/^ */- /;H;};$b0'$'\n'' d;:0'$'\n'' x;/APPLE [^:]+$/d;p;' ' /^find: /d;p;' );c1=(system_profiler pmset\ -g nvram fdesetup find syslog df vm_stat sar ps sudo\ crontab sudo\ iotop top pkgutil 'PlistBuddy 2>&1 -c "Print' whoami cksum kextstat launchctl sudo\ launchctl crontab 'sudo defaults read' stat lsbom mdfind ' for i in ${p[24]};do ${c1[18]} ${c2[27]} $i;done;' defaults\ read scutil sudo\ dtrace sudo\ profiles sed\ -En awk /S*/*/P*/*/*/C*/*/airport networksetup mdutil sudo\ lsof test );c2=(com.apple.loginwindow\ LoginHook '" /L*/P*/loginw*' '" L*/P*/*loginit*' 'L*/Ca*/com.ap*.Saf*/E*/* -d 1 -name In*t -exec '"${c1[14]}"' :CFBundleDisplayName" {} \;|sort|uniq' '~ $TMPDIR.. \( -flags +sappnd,schg,uappnd,uchg -o ! -user $UID -o ! -perm -600 \)' '.??* -path .Trash -prune -o -type d -name *.app -print -prune' :${p[35]}\" :Label\" '{/,}L*/{Con,Pref}* -type f ! -size 0 -name *.plist -exec plutil -s {} \;' "-f'%N: %l' Desktop L*/Keyc*" therm sysload boot-args status " -F '\$Time \$Message' -k Sender kernel -k Message Req 'bad |Beac|caug|dead[^bl]|FAIL|fail|GPU |hfs: Ru|inval|jnl:|last value [1-9]|n Cause: -|NVDA\(|pagin|proc: t|Roamed|rror|ssert|Thrott|tim(ed? ?|ing )o|WARN' -k Message Rne 'Goog|ksadm|SMC:' -o -k Sender fseventsd -k Message Req 'SL' " '-du -n DEV -n EDEV 1 10' 'acrx -o comm,ruid,%cpu' '-t1 10 1' '-f -pfc /var/db/r*/com.apple.*.{BS,Bas,Es,J,OSXU,Rem,up}*.bom' '{/,}L*/Lo*/Diag* -type f -regex .\*[cgh] ! -name *ag \( -exec grep -lq "^Thread c" {} \; -exec printf \* \; -o -true \) -execdir stat -f:%Sc:%N -t%F {} \;|sort -t: -k2 |tail -n'${p[38]} '-L {/{S*/,},}L*/Lau* -type f' '-L /{S*/,}L*/StartupItems -type f -exec file {} +' '-L /S*/L*/{C*/Sec*A,E}* {/,}L*/{A*d,Ca*/*/Ex,Compon,Ex,In,iTu,Keyb,Mail/B,P*P,Qu*T,Scripti,Sec,Servi,Spo,Widg}* -type f -name Info.plist' '/usr/lib -type f -name *.dylib' `awk "${s[31]}"<<<${p[23]}` "/e*/{auto,{cron,fs}tab,hosts,{[lp],sy}*.conf,pam.d/*,ssh{,d}_config,*.local} {,/usr/local}/etc/periodic/*/* /L*/P*{,/*}/com.a*.{Bo,sec*.ap}*t /S*/L*/Lau*/*t .launchd.conf" list getenv /Library/Preferences/com.apple.alf\ globalstate --proxy '-n get default' -I --dns -getdnsservers\ "${p[N5]}" -getinfo\ "${p[N5]}" -P -m\ / '' -n1 '-R -l1 -n1 -o prt -stats command,uid,prt' '--regexp --only-files --files com.apple.pkg.*|sort|uniq' -kl -l -s\ / '-R -l1 -n1 -o mem -stats command,uid,mem' -i4TCP:0-1023 com.apple.dashboard\ layer-gadgets '-d /L*/Mana*/$USER&&echo On' '-app Safari WebKitDNSPrefetchingEnabled' );N1=${#c2[@]};for j in {0..9};do c2[N1+j]=SP${p[j]}DataType;done;N2=${#c2[@]};for j in 0 1;do c2[N2+j]="-n ' syscall::'${p[33+j]}':return { @out[execname,uid]=sum(arg0) } tick-10sec { trunc(@out,1);exit(0);} '";done;l=(Restricted\ files Hidden\ apps 'Elapsed time (s)' POST Battery Safari\ extensions Bad\ plists 'High file counts' User Heat System\ load boot\ args FileVault Diagnostic\ reports Log 'Free space (MiB)' 'Swap (MiB)' Activity 'CPU per process' Login\ hook 'I/O per process' Mach\ ports kexts Daemons Agents launchd Startup\ items Admin\ access Root\ access Bundles dylibs Apps Font\ issues Inserted\ dylibs Firewall Proxies DNS TCP/IP Wi-Fi Profiles Root\ crontab User\ crontab 'Global login items' 'User login items' Spotlight Memory Listeners Widgets Parental\ Controls Prefetching SATA );N3=${#l[@]};for i in 0 1 2;do l[N3+i]=${p[5+i]};done;N4=${#l[@]};for j in 0 1;do l[N4+j]="Current ${p[29+j]}stream data";done;A0() { id -G|grep -qw 80;v[1]=$?;((v[1]==0))&&sudo true;v[2]=$?;v[3]=`date +%s`;clear >&-;date '+Start time: %T %D%n';};for i in 0 1;do eval ' A'$((1+i))'() { v=` eval "${c1[$1]} ${c2[$2]}"|'${c1[30+i]}' "${s[$3]}" `;[[ "$v" ]];};A'$((3+i))'() { v=` while read i;do [[ "$i" ]]&&eval "${c1[$1]} ${c2[$2]}" \"$i\"|'${c1[30+i]}' "${s[$3]}";done<<<"${v[$4]}" `;[[ "$v" ]];};A'$((5+i))'() { v=` while read i;do '${c1[30+i]}' "${s[$1]}" "$i";done<<<"${v[$2]}" `;[[ "$v" ]];};';done;A7(){ v=$((`date +%s`-v[3]));};B2(){ v[$1]="$v";};for i in 0 1;do eval ' B'$i'() { v=;((v['$((i+1))']==0))||{ v=No;false;};};B'$((3+i))'() { v[$2]=`'${c1[30+i]}' "${s[$3]}"<<<"${v[$1]}"`;} ';done;B5(){ v[$1]="${v[$1]}"$'\n'"${v[$2]}";};B6() { v=` paste -d: <(printf "${v[$1]}") <(printf "${v[$2]}")|awk -F: ' {printf("'"${f[$3]}"'",$1,$2)} ' `;};B7(){ v=`grep -Fv "${v[$1]}"<<<"$v"`;};C0(){ [[ "$v" ]]&&echo "$v";};C1() { [[ "$v" ]]&&printf "${f[$1]}" "${l[$2]}" "$v";};C2() { v=`echo $v`;[[ "$v" != 0 ]]&&C1 0 $1;};C3() { v=`sed -E "$s"<<<"$v"`&&C1 1 $1;};for i in 1 2;do for j in 2 3;do eval D$i$j'(){ A'$i' $1 $2 $3; C'$j' $4;};';done;done;{ A0;A2 0 $((N1+1)) 2;C0;A1 0 $N1 1;C0;B0;C2 27;B0&&! B1&&C2 28;D12 15 37 25 8;A1 0 $((N1+2)) 3;C0;D13 0 $((N1+3)) 4 3;D23 0 $((N1+4)) 5 4;D13 0 $((N1+9)) 59 50;for i in 0 1 2;do D13 0 $((N1+5+i)) 6 $((N3+i));done;D13 1 10 7 9;D13 1 11 8 10;D22 2 12 9 11;D12 3 13 10 12;D23 4 19 44 13;D23 5 14 12 14;D22 6 36 13 15;D22 7 37 14 16;D23 8 15 38 17;D22 9 16 16 18;B1&&{ D22 11 17 17 20;for i in 0 1;do D22 28 $((N2+i)) 45 $((N4+i));done;};D22 12 44 54 45;D22 12 39 15 21;A1 13 40 18;B2 4;B3 4 0 19;A3 14 6 32 0;B4 0 5 11;A1 17 41 20;B7 5;C3 22;B4 4 6 21;A3 14 7 32 6;B4 0 7 11;B3 4 0 22;A3 14 6 32 0;B4 0 8 11;B5 7 8;B1&&{ A2 19 26 23;B7 7;C3 23;};A2 18 26 23;B7 7;C3 24;A2 4 20 21;B7 6;B2 9;A4 14 7 52 9;B2 10;B6 9 10 4;C3 25;D13 4 21 24 26;B4 4 12 26;B3 4 13 27;A1 4 22 29;B7 12;B2 14;A4 14 6 52 14;B2 15;B6 14 15 4;B3 0 0 30;C3 29;A1 4 23 27;B7 13;C3 30;D13 24 24 32 31;D13 25 37 32 33;A2 23 18 28;B2 16;A2 16 25 33;B7 16;B3 0 0 34;B2 21;A6 47 21&&C0;B1&&{ D13 21 0 32 19;D13 10 42 32 40;D22 29 35 46 39;};D13 14 1 48 42;D12 34 43 53 44;D22 0 $((N1+8)) 51 32;D13 4 8 41 6;D12 26 28 35 34;D13 27 29 36 35;A2 27 32 39&&{ B2 19;A2 33 33 40;B2 20;B6 19 20 3;};C2 36;D23 33 34 42 37;B1&&D23 35 45 55 46;D23 32 31 43 38;D12 36 47 32 48;D13 20 42 32 41;D13 14 2 48 43;D13 4 5 32 1;D13 4 3 60 5;D12 26 48 49 49;B3 4 22 57;A1 26 46 56;B7 22;B3 0 0 58;C3 47;D22 4 4 50 0;D23 22 9 37 7;A7;C2 2;} 2>/dev/null|pbcopy;exit 2>&-

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

7. 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. Click Utilities, then Terminal in the icon grid.

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.

8. 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.

9. 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, press the key combination control-C or 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.

10. 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, there will be nothing in the Terminal window and no indication of progress. Wait for the line

[Process completed]

to appear. If you don't see it within half an hour or so, the test probably won't complete in a reasonable time. In that case, close the Terminal window and report the results. No harm will be done.

11. When the test is complete, 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.

12. 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.

Note: 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 don't necessarily agree with them.

________________________________

Copyright © 2014 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.

A.

The system is so heavily modified by third-party software that, instead of trying to remove the modifications piecemeal, you should erase the startup volume, reinstall OS X, and then go through the initial setup process, restoring only user data and settings from a backup—not applications or other files. This course of action will be easier and more reliable than trying to clean up a messy system.

Back up all data to at least two different storage devices, if you haven't already done so. One backup is not enough to be safe. The backups can be made with Time Machine or with Disk Utility. Preferably both.

Erase and install OS X. This operation will destroy all data on the startup volume, so you had be better be sure of the backups. If you upgraded from an older version of OS X, you'll need the Apple ID and password that you used, so make a note of those before you begin.

When you restart, you'll be prompted to go through the initial setup process in Setup Assistant. That’s when you transfer the data from a backup.

Select only users and Computer & Network Settings in the Setup Assistant dialog—not Applications or Other files and folders. Don't transfer the Guest account, if it was enabled.

After that, run Software Update.

If the problem is resolved after the clean installation, reinstall third-party software selectively. I can only suggest general guidelines. Self-contained applications that install into the Applications folder by drag-and-drop or download from the App Store are usually safe. Anything that comes packaged as an installer or that prompts for an administrator password is suspect, and you must test thoroughly after reinstalling each such item to make sure you haven't restored the problem.

I strongly recommend that you never reinstall commercial "security" products or "utilities," nor any software that changes the user interface or the behavior of built-in applications such as Safari. If you do that, the problem is likely to recur.

Before installing any software, ask yourself the question: "Am I sure I know how to uninstall this without having to wipe the volume again?" If the answer is "no," stop.

Never install any third-party software unless you know how to uninstall it.

B.

The battery must be replaced.

C.

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.

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 nouchg,nouappnd,noschg,nosappnd {} + -exec chown $UID {} + -exec chmod +rw {} + -exec chmod -N {} + -type d -exec chmod +x {} + 2>&-

This time 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:

res

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.

D.

Depending on what they are, keeping many files on the Desktop can slow down the user interface. I suggest you move most or all of those files into other folders.

It's not clear whether you took any of the steps I suggested.

but now my battery capacity and charge are both shown as 65205mAh all the time. Resetting the SMC also doesn't seem to work.

That number is an error value and indicates a failed battery. The only cure is a new battery.

I attach two monitors to my 2012 Retina MacBook Pro running OS X 10.10.3. I can bear out that its performance is dramatically better when I keep the laptop closed when I attach the monitors. Time Machine runs much faster, and starting the Eclipse Java IDE does not spike the load average. Thanks, Linc Davis!

Drop this line of code into Terminal if you have a 2012 or later Mac and are having issues with kernel_task overusing the CPU.

sudo mv /System/Library/Extensions/IOPlatformPluginFamily.kext/ ~

It worked on my mid 2012 MacBook Pro with OS X 10.11.6. After many different attempts (reformat, SMC reset, battery check, RAM reseating, etc.) to fix the kernel_task throttling, I was surprised to see a single line of code do the job. Note that a restart is required!