Q: Vertical Jagged Lines during Boot

Hello,

My Early 2011 MacBook Pro 15" recently showed vertical lines that were zig-zagged in shape. The color looked a little tinted (barely) and the vertical black divider bar you see when you four-finger swipe between desktops appeared intermittently. Eventually after 5 minutes it would go back to normal. This happened 2 or 3 times in a weeks time, then didn't happen again for a couple weeks. When it recurred then, it stayed longer and eventually repeated again.

Now, the last time I checked, after having an Apple Authorized Service Center run diagnostics (file system and hard drive checked OK, they said "This issue is notorious for this particular model at this age") it sat on the progress bar Apple logo screen for 2+ hours halfway through with the zig-zag lines before I powered it down for good.

The thing that bothers me is that the service tech said it's common for this computer at this age. How likely is it that he knows that for sure given that all Early 2011 MacBook Pro's today are the same age and I can't imagine them having experienced this often enough to use that as their diagnosis.

Anyone have experience or thoughts about this?