Who likes major diagnostic challenges?

Discussion in 'OS X Mountain Lion (10.8)' started by Benbikeman, Sep 8, 2012.

  1. Benbikeman macrumors 6502a

    Benbikeman

    Joined:
    May 17, 2011
    Location:
    London, England
    #1
    I'm tearing my hair out here, as I have a problem which has some symptoms which suggest it must be software and some symptoms which suggest it must be hardware. Despite two visits to Apple Stores and numerous calls to AppleCare, we're no closer to a diagnosis a week later.

    Setup:
    MacBook Pro 17 with 2 x 1Tb drives (drive 2 in DVD bay)
    Booting from drive 1 in main bay
    OSX 10.8.1

    Original symptoms:
    Kernal panics, followed by boot volume on drive 1 being intermittently mountable

    What we have done so far:

    Replaced physical drive
    Clean install of OS X, and did a migration of everything except settings
    Same symptoms

    Clean install of OS X on drive 2
    Runs perfectly with nothing else installed

    Put original drive back in drive 1
    Clean install of OS X on that drive
    Runs perfectly with nothing else installed

    Created a partition on drive 2, clean install of OS X in that partition
    Migrated everything back to that partition
    Same symptoms when booting from that partition
    NB: Different physical drive, different physical drive bay
    This suggests software rather than hardware, but it doesn't end there ...

    On drive 1:
    Reinstalled Thunderbird (can explain why this and not Mail if anyone cares)
    All ok

    Manually copying data ONLY from Time Machine then gets crashes:
    Thunderbird first
    Then Safari
    Neither window disappears even when force-quit processes
    Crash Report showing 100% CPU but no disk activity
    Any app opened in that time would run but not quit (eg. Activity Monitor)
    Shutdown did nothing, had to do a hard shutdown

    Booting into Utilities, Disk Utilities can't unmount the volume on drive 1

    Review so far:
    Clean install on either drive runs fine with both Thunderbird and Safari installed
    But both apps crash when data is copied back
    Drive 1 mount problems return when the data is back on it
    BUT the data is just that, documents only, no apps or settings

    What I want to do at this stage is erase drive 1 again, clean install OSX again, run Mail rather than Thunderbird, make sure that system is stable, then copy data back (manually) then see if that is stable, but it's all feeling rather trial-and-error.

    Anyone have any bright ideas?

    Ben
     
  2. ljonesj macrumors 6502a

    ljonesj

    Joined:
    Oct 20, 2009
    Location:
    Kingsport TN
    #2
    sounds like the info for thunderbird data is corrupted that is causing panics

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    sounds like the info for thunderbird data is corrupted that is causing panics
     
  3. Benbikeman thread starter macrumors 6502a

    Benbikeman

    Joined:
    May 17, 2011
    Location:
    London, England
    #3
     
  4. Benbikeman thread starter macrumors 6502a

    Benbikeman

    Joined:
    May 17, 2011
    Location:
    London, England
    #4
    Finally solved!

    It was faulty RAM.

    Because the initial symptom was the boot volume refusing to mount, it was initially pointing to the drive or drive-related hardware. When the same symptoms occurred when migrating to a new drive in a new bay, we then thought software.

    But I think what happened is that the first crash corrupted something on the boot volume in such a way that the corrupted file was also migrated back. The really odd thing was a vanilla install running fine for a while, but that now appears to be coincidence.

    Memtest reported shedloads of errors on the RAM. I swapped back to the original 4Gb and ran it again, getting a clean result. The machine has now been running for 12 hours with the original RAM without a crash (crashes were previously happening once every 1-2 hours).

    Now I have a clean install on drive 2, I shall migrate back to drive 1 and just see whether that works. It may be there was some weird combination of a corrupted file and bad RAM causing the crash on the new drive, so we shall see. Worst-case, I reinstall apps and settings manually on drive 2, clone that to drive 1 and am back in action.
     

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