I have a MacBook 7,1 which i recently installed a PNY 250 SSD and added some RAM. The laptop was running awesome with OSX 10.6.8, lightning fast.
Then I installed Yosemite. There was a bit of hang during the install, but Yosemite came up no issue when I rebooted. Here is the problem:
Every other time I boot the MacBook it hangs at a grey screen with the prohibitory sign. Verbose reveals a "still waiting for root device" error. Now if I reboot from that hang, it boots fine, but then will hang again the next time. It keeps alternating like this. Any ideas??
I am not running any third party trim software, so that's not the issue.