Hello everyone. I am pleased to have stumbled across this post the other day. After going through this last year, I have not used this laptop since the summer.
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Today was the first time I have turned this 2011 MacBook Pro on since then. I updated to Yosemite and that is about it. So far after powering up I have not experienced any graphical issues. I've yet to plug it into my external monitor, where she really got buggered up.
I spoke to Apple and will be taking this machine in to get diagnosed. Here is what I am worried about. I haven't seen any artifacts yet, but when I used this machine regularly the above screen shot was normal behaviour.
I just ran the Apple Hardware Test (not the extended version) and no errors were returned. How is this possible? Do y'all think they will be running the same tests? Should I run the extended test?
Maybe I am tripping but it just blows me away that so far I haven't seen any artifacts after not using this machine for months.
Anyways I will keep y'all posted on how the diagnosis goes tomorrow...was a little stumped by this.