Please help - White screen only unless I boot is safe mode

The main difference between "regular" mode and "Safe mode" is that only a minimal set of Apple-only kernel extensions are loaded in Safe mode. It was intended that after you installed something deadly, you could get control of your Mac again in Safe mode, and set things right.

Have you installed anything recently? What non-Apple extension have you added?

1. This procedure is a diagnostic test. It changes nothing, for better or worse, and therefore will not, in itself, solve the problem.

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. 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 request of a stranger on a public message board. 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 from this web page into the window of another application. Wait for the script to run. It usually takes a few minutes. Then paste the results, which will have been copied automatically, back into a reply on this page. The sequence is: copy, paste, wait, paste again. Details follow.

4. You may have started the computer in "safe" mode. Preferably, these steps should be taken in “normal” 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.

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.

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; clear; Fb='%s\n\t(%s)\n'; Fm='\n%s\n\n%s\n'; Fr='\nRAM details\n%s\n'; Fs='\n%s: %s\n'; Fu='user %s%%, system %s%%'; PB="/usr/libexec/PlistBuddy -c Print"; A () { [[ a -eq 0 ]]; }; M () { find -L "$d" -type f | while read f; do file -b "$f" | egrep -lq XML\|exec && echo $f; done; }; Pc () { o=`grep -v '^ *#' "$2"`; l=`wc -l <<< "$o"`; [[ l -gt 25 ]] && o=`head -n25 <<< "$o"`$'\n'"[$((l-25)) more line(s)]"; Pm "$1"; }; Pm () { [[ "$o" ]] && o=`sed -E '/^ *$/d; s/^ */ /; s/[-0-9A-Fa-f]{22,}/UUID/g' <<< "$o"` && printf "$Fm" "$1" "$o"; }; Pp () { o=`$PB "$2" | awk -F'= ' \/$3'/{print $2}'`; Pm "$1"; }; Ps () { o=`echo $o`; [[ ! "$o" =~ ^0?$ ]] && printf "$Fs" "$1" "$o"; }; R () { o=; [[ r -eq 0 ]]; }; SP () { system_profiler SP${1}DataType; }; id -G | grep -qw 80; a=$?; A && sudo true; r=$?; t=`date +%s`; clear; { A || echo $'No admin access\n'; A && ! R && echo $'No root access\n'; SP Software | sed '8!d;s/^ *//'; o=`SP Hardware | awk '/Mem/{print $2}'`; o=$((o<4?o:0)); Ps "Total RAM (GB)"; o=`SP Memory | sed '1,5d;/[my].*:/d'`; [[ "$o" =~ s:\ [^O]|x([^08]||0[^2]8[^0]) ]] && printf "$Fr" "$o"; o=`SP Diagnostics | sed '5,6!d'`; [[ "$o" =~ Pass ]] || Pm "POST"; p=`SP Power`; o=`awk '/Cy/{print $NF}' <<< "$p"`; o=$((o>=300?o:0)); Ps "Battery cycles"; o=`sed -n '/Cond.*: [^N]/{s/^.*://p;}' <<< "$p"`; Ps "Battery condition"; for b in Thunderbolt USB; do o=`SP $b | sed -En '1d;/:$/{s/ *:$//;x;s/\n//p;};/^ *V.* [0N].* /{s/ 0x.... //;s/[()]//g;s/(.*: )(.*)/ \(\2\)/;H;};/Apple|Genesy|SMSC/{s/.//g;h;}'`; Pm $b; done; o=`pmset -g therm | sed 's/^.*C/C/'`; [[ "$o" =~ No\ th|pms ]] && o=; Pm "Thermal conditions"; o=`pmset -g sysload | grep -v :`; [[ "$o" =~ =\ [^GO] ]] || o=; Pm "System load advisory"; o=`nvram boot-args | awk '{$1=""; print}'`; Ps "boot-args"; a=(/ ""); A=(System User); for i in 0 1; do o=`cd ${a[$i]}L*/Lo*/Diag* || continue; for f in *.{cr,h,pa,s}*; do [[ -f "$f" ]] || continue; d=$(awk '/^D/{print $2; exit}' "$f"); [[ "$f" =~ h$ ]] && grep -lq "^Thread c" "$f" && e=\* || e=; echo $d ${f%_$d*} ${f##*.} "$e"; done | sort | tail`; Pm "${A[$i]} diagnostics"; done; [[ "$o" =~ \*$ ]] && printf $'\n* Code injection\n'; o=`syslog -F bsd -k Sender kernel -k Message CReq 'GPU |hfs: Ru|I/O e|last value [1-9]|n Cause: -|NVDA\(|pagin|SATA W|ssert|Thrott|timed? ?o' | tail -n25 | awk '/:/{$4=""; $5=""};1'`; Pm "Kernel messages"; o=`df -m / | awk 'NR==2 {print $4}'`; o=$((o<5120?o:0)); Ps "Free space (MiB)"; o=$(($(vm_stat | awk '/eo/{sub("\\.",""); print $2}')/256)); o=$((o>=1024?o:0)); Ps "Pageouts (MiB)"; s=( `sar -u 1 10 | sed '$!d'` ); [[ s[4] -lt 85 ]] && o=`printf "$Fu" ${s[1]} ${s[3]}` || o=; Ps "Total CPU usage" && { s=(`ps acrx -o comm,ruid,%cpu | sed '2!d'`); n=$((${#s[*]}-1)); c="${s[*]}"; o=${s[$n]}%; Ps "CPU usage by process \"${c% ${s[$((n-1))]}*}\" with UID ${s[$((n-1))]}"; }; s=(`top -R -l1 -n1 -o prt -stats command,uid,prt | sed '$!d'`); n=$((${#s[*]}-1)); s[$n]=${s[$n]%[+-]}; c="${s[*]}"; o=$((s[$n]>=25000?s[$n]:0)); Ps "Mach ports used by process \"${c% ${s[$((n-1))]}*}\" with UID ${s[$((n-1))]}"; o=`kextstat -kl | grep -v com\\.apple | cut -c53- | cut -d\< -f1`; Pm "Loaded extrinsic kernel extensions"; R && o=`sudo launchctl list | awk 'NR>1 && !/0x|com\.(apple|openssh|vix\.cron)|org\.(amav|apac|calendarse|cups|dove|isc|ntp|post[fg]|x)/{print $3}'`; Pm "Extrinsic daemons"; o=`launchctl list | awk 'NR>1 && !/0x|com\.apple|org\.(x|openbsd)|\.[0-9]+$/{print $3}'`; Pm "Extrinsic agents"; o=`for d in {/,}L*/Lau*; do M; done | grep -v com\.apple\.CSConfig | while read f; do ID=$($PB\ :Label "$f") || ID="No job label"; printf "$Fb" "$f" "$ID"; done`; Pm "launchd items"; o=`for d in /{S*/,}L*/Star*; do M; done`; Pm "Startup items"; o=`find -L /S*/L*/{C*/Sec*A,E}* {/,}L*/{A*d,Compon,Ex,In,iTu,Keyb,Mail/B,P*P,Qu*T,Scripti,Sec,Servi,Spo}* -type d -name Contents -prune | while read d; do ID=$($PB\ :CFBundleIdentifier "$d/Info.plist") || ID="No bundle ID"; [[ "$ID" =~ ^com\.apple\.[^x]|Accusys|ArcMSR|ATTO|HDPro|HighPoint|driver\.stex|hp-fax|\.hpio|JMicron|microsoft\.MDI|print|SoftRAID ]] || printf "$Fb" "${d%/Contents}" "$ID"; done`; Pm "Extrinsic loadable bundles"; o=`find -L /u*/{,*/}lib -type f | while read f; do file -b "$f" | grep -qw shared && ! codesign -v "$f" && echo $f; done`; Pm "Unsigned shared libraries"; o=`for e in INSERT_LIBRARIES LIBRARY_PATH; do launchctl getenv DYLD_$e; done`; Pm "Environment"; o=`find -L {,/u*/lo*}/e*/periodic -type f -mtime -10d`; Pm "Modified periodic scripts"; o=`scutil --proxy | grep Prox`; Pm "Proxies"; o=`scutil --dns | awk '/r\[0\] /{if ($NF !~ /^1(0|72\.(1[6-9]|2[0-9]|3[0-1])|92\.168)\./) print $NF; exit}'`; Ps "DNS"; R && o=`sudo profiles -P | grep : | wc -l`; Ps "Profiles"; f=auto_master; [[ `md5 -q /etc/$f` =~ ^b166 ]] || Pc $f /etc/$f; for f in fstab sysctl.conf crontab launchd.conf; do Pc $f /etc/$f; done; Pc "hosts" <(grep -v 'host *$' /etc/hosts); Pc "User launchd" ~/.launchd*; R && Pc "Root crontab" <(sudo crontab -l); Pc "User crontab" <(crontab -l | sed -E 's:/Users/[^/]+/:/Users/USER/:g'); R && o=`sudo defaults read com.apple.loginwindow LoginHook`; Pm "Login hook"; Pp "Global login items" /L*/P*/loginw* Path; Pp "User login items" L*/P*/*loginit* Name; Pp "Safari extensions" L*/Saf*/*/E*.plist Bundle | sed -E 's/(\..*$|-[1-9])//g'; o=`find ~ $TMPDIR.. \( -flags +sappnd,schg,uappnd,uchg -o ! -user $UID -o ! -perm -600 \) | wc -l`; Ps "Restricted user files"; cd; o=`SP Fonts | egrep "Valid: N|Duplicate: Y" | wc -l`; Ps "Font problems"; o=`find L*/{Con,Pref}* -type f ! -size 0 -name *.plist | while read f; do plutil -s "$f" >&- || echo $f; done`; Pm "Bad plists"; d=(Desktop L*/Keyc*); n=(20 7); for i in 0 1; do o=`find "${d[$i]}" -type f -maxdepth 1 | wc -l`; o=$((o<=n[$i]?0:o)); Ps "${d[$i]##*/} file count"; done; o=; [[ UID -eq 0 ]] && o=root; Ps "UID"; o=$((`date +%s`-t)); Ps "Elapsed time (s)"; } 2>/dev/null | pbcopy; exit 2>&-

exec bash

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, just press return three times at the password prompt.

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 will 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.

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 the message, "You have included content in your post that is not permitted." It means that the forum software has misidentified something in the post as a violation of the rules. If that happens, 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.

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I'll assume that you don't want to carry out the test I suggested.

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 a mirroring tool such as "Carbon Copy Cloner." Preferably both.