Flickering Pink background on all windows. Yosemite 10.10.1 Ever since upgrading my mid 2009 MacBook Pro from OS 10.6.8 to 10.10.1 Yosemite, the backgrounds to all my windows are vibrating flickering pink which is quite undesirable. At first I thought it was the acid flashbacks they promised me in high school but it's definitely only on my computer

Seriously, though, any idea as to why and any fixes?

I have reset my PRAM
Sounds like a GPU/driver mismatch, back buffer issue, or potential imminent failure.

Or it could be that GPU just isn't up to the task, running out of memory &amp; refilling the buffers constantly.

Try System Prefs > Accessibility > Display &amp; Reduce Transparency.