I have an Imac mid 2011 with an ati radeon hd 6770m.
Just recentley I have been getting random pink and green squares.
If I go over them with the mouse the mouse covers them as if they are in the background. I also tried taking a screenshot and they do not appear?
Any ideas? if I position the windows in certain places more appear?
It is baffling me.
The mac has not crashed once in 3 years and has been working fine