Out of nowhere, my MacBook Pro 2011 unibody running 10.7.5 began to crash. After the crashes, in the boot sequence you could see very thin horizontal red lines. The red lines were so thin that I can't take a picture as the lines won't show up in photos. While you could see the red lines across the screen, the computer will not boot up, not even to recovery. After leaving the computer off for a few hours, it will boot-up like nothing happened.

After diagnosis of the whole comp, it turned out I had over 60 bad sectors and naturally I needed a new hard drive, although at first it was suspected that I had a bad graphics card. So a new hard drive was installed and the computer was working 100% ok again. However, as soon as I migrated my old user from the backups and logged into the migrated user, the computer began to crash in exactly the same way as before.

The waits between when the computer could finally boot up became longer and longer, up to 24hrs.

Now this is the interesting part, the computer works completely fine when I'm logged in into the default user that I have from installing the new hard drive, it's as soon as I log into the migrated user that the computer completely blocks up.

I thought maybe the ram has gone bad, so I checked it with memtest and it seems to be completely ok. I then checked the temperatures while running a stress test. and Although the CPU cores under max load reach up 95ºC, the heatsinks manage just fine staying at 50ºC. While playing HD videos the graphics processor is staying relatively cool without any spikes in temp.

I check the permissions of the disk and I did find a massive amount of errors which I repaired but apart from that there shouldn't be anything wrong since it's a new hard drive.


  1. 2011 MacBook Pro 10.7.5 crashed — shows very thin, horizontal red lines across screen.
  2. Full diagnosis revealed bad sectors in HD. Graphics, RAM, CPU, and temps are ok.
  3. After installing new HD everything worked fine.
  4. After migration, when using the old user from the migration (backup), the computer crashes again.
  5. Using default user results in no crashes.

2 Answers 2


I recently had this issue. It turns out that Apple has a repair program for this issue at no cost that runs until Dec 31, 2016. Here is the link: https://www.apple.com/support/macbookpro-videoissues/

I took my laptop in to the nearest Apple Store. The Genius Bar tech ran a diagnostic test to verify the issue. They sent it to a repair location in Texas and in 3-5 days I had it back. There is also a 90 warranty on the work.


Thin horizontal red lines on boot doesn't sound like a hard drive issue. It's possible that you have two separate issues with your Macbook.

It sounds like there's an issue with your CPU/graphics/mainboard. This would explain the need to wait for an extended period of time before another successful boot. If you ask me, 95 deg. C is way too hot! Perhaps the heatsink is loose or the fans are clogged. The fact that you could log into the default user without issue is perhaps just a coincidence; maybe you weren't logged into that account long enough to notice any problems.

  • The thing is, I have installed a clean version of Mavericks and I have been running it for quite some time now and it still hasn't crashed. It's as soon as I even look at the data in the time-machine backup that everything starts to go horribly wrong. Is it possible that data can become so corrupted that it causes this kind of crash? I have installed a bunch of programs, played 1080p HD videos, and ran some highly CPU intensive process and still nothing and all diagnostics are passing. Is there some way that I can diagnose the CPU performance apart from straining it to see what happens?
    – DGDD
    Commented Dec 27, 2013 at 21:59
  • Also, remember that the 95C is right at the CPU diode.
    – DGDD
    Commented Dec 27, 2013 at 22:05
  • That's still way too high. The CPU shouldn't be peaking past 70C. While it's PLAUSABLE that some kind of corrupted data is causing the Mac to crash, I highly doubt it. This is most likely a hardware issue.
    – Bigbio2002
    Commented Dec 30, 2013 at 16:43

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