2011 Mac Mini Random Boot/Graphics Problems
I am having an intermittent problem booting all the way to the Mac Mini desktop. If I can boot to the desktop, the graphics get wonky or go to the white screen after various time and activity.
I have exhausted my knowledge to figure out what is wrong.
2011 Mac Mini / 2.5 i5 / Radeon 6630M / 4 GB memory / Toshiba 500GB HD / OS 10.8.5 All software is up to date.
On the failed boot, I power on, I get the Apple, then after about 30 sec. of spinning graphic, just white screen.
On successful boot, I have used single user fsck, safe boot, reset PRAM, reset SMC and various combinations. Sometimes it boots, sometimes it doesn’t. I have never been able to successfully use the Recovery mode.
I have repaired permissions, verified the HD, run a successful hardware test, run fsck -fy. All tests say the hard drive and memory are ok.
I have tested the monitor by connecting two different known good monitors and sets of cables through the HDMI port or the Thunderbolt port. This makes no difference to the boot.
When it boots properly, I can use the desktop for minutes or hours.
The computer being hot or cold doesn’t seem to make a difference. Letting the cpu sit or powering on right after a power down doesn't make a difference.
I have used a different known good Apple keyboard and Logitech optical mouse.
I have unplugged all peripherals except keyboard and mouse.
Sometimes when it stalls at the white screen, I can network from another computer and connect to the Mini, where I can see files only, no desktop.
If the Mini boots to the desktop, I can screen share from another computer and see the desktop activity. When the graphics go wonky on the Mini monitor, the screen share looks okay.
Anything else I can try?