Missing system icons
Hello, i have weird problem with my Macbook Air 11' mid 2011. My menubar icons (like wireless, bluetooth) and system icons (arrows in finder, itunes etc) are missing. If i create fresh profile this problem is gone for a while (few days). Reinstall fixes this issue for months. One of the symptomes is corrupted graphic in login window (after screensaver starts, you have to type password).
What i tried:
* clean caches
* fix drive in single user mode via fsck
* create fresh profile
* uninstall all software except system software
* repair permissions
* remove finder plist
Missing icons in finder:
Corrupted google logo:
Menubar:
Previous stage of menubar issue:
Safari:
Do you think this might be a hardware issue? If it is software issue, i'm not sure how to reproduce it. It just happens sometimes, i'm not aware of actions which might cause it.
Thanks for your replies.
MacBook Air (11-INCH, MID 2011), OS X Mountain Lion (10.8.2)