OSX hangs on startup after large file search caused a crash (Mavericks 10.9.5) Well, my computer won't startup. Gray screen on regular startups, black screen with no cursor on safe mode startup.

It started after a everything froze while performing a massive file search in finder. I was looking through all pictures before Jan. 1st last year -- gigs and gigs and gigs of data -- and I was in the Cover Flow view. I noticed everything was slowing down, and while I was browsing, I tried opening a couple files, both in preview and in Photoshop. Both programs hung and eventually crashed.

Eventually, finder itself froze completely. I hard reset. Now, nothing boots.

I've tried moving the preferences files from Library/Preferences (finder, dock, systempreferences), no go. I tried moving the /Library/Preferences/com.apple.loginwindow.plist file and /Library/Preferences/com.apple.windowserver.plist file. No go.

I deleted all the caches from /Library, /System/Library, and /Users/myusername/Library/Caches.

Checked my hard drive with fsck and everything is fine. Also tried /usr/libexec/repair_packages --repair --standard-pkgs. Nada.

My last line in my boot log is UserEventAgent[11]: Captive: CNPluginHandler en1: Inactive.

If I boot to safe mode, the progress bar loads, it hangs on the gray screen for a while, it flashes blue for a split second and then hangs on the black screen.

Regular boot just hangs on the gray screen.

Any ideas?
It boots! I finally found a thread of others with identical symptoms: Gray screen on normal boot, blue screen with lines even when booting to recovery, crazy fan spinning. 

It was my GPU.

Standard problem for this model of macbook, and Apple willfully ignores it. 

Instructions on how to fix it can be found in this thread.

I'm reposting them here for the sake of making this information as widely available as possible.

Disable your AMD graphics card by doing the following (it'll force you to use your intel graphics card instead -- not powerful, but functional).

/sbin/fsck -fy /
/sbin/mount -uw /
mkdir /Disabled_System_Library_Extensions
cd /Disabled_System_Library_Extensions
mv /System/Library/Extensions/ATI* .
mv /System/Library/Extensions/AMD* .
touch /System/Library/Extensions
exit


Reboot and your computer will startup as normal.