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Lion: external drive no longer bootable - Time Machine?

1627 Views 5 Replies Latest reply: May 21, 2012 1:31 AM by Philip Keller RSS
Philip Keller Level 1 Level 1 (0 points)
Currently Being Moderated
Apr 8, 2012 4:39 AM

I installed a recovery copy of Lion on an external USB drive, and although it shows up as a potential startup disk in System Preferences, I can't boot from it. When I select it as the startup disk in System Preferences and reboot, I end up booting from the internal drive. When I hold down ALT when booting, I see the access light on the USB drive blink a few times, but it doesn't show up in the bootable volumes list.


The following Knowledge Base article makes me think my problem is that I use the same volume for Time Machine backups:

Is that the problem?


For completeness, here's how I got myself into this mess:

  1. Finally upgraded to Lion (had to, because MobileMe is going away :-(
  2. I got the "Some features of Mac OS X Lion are not supported for the disk" error (see
  3. So I installed Lion on an external recovery drive, as per
  4. I had been using this drive for Time Machine backups, so I copied Backups.backupdb off to yet another volume before reformatting.
  5. After installing Lion, I copied Backups.backupdb back, at the root of the external drive. When I connected the drive, Time Machine posted a warning that the disk ID had changed; I said proceed, and backups resumed normally.
  6. Now I discovered that I can't boot from my recovery drive. Grrr...


I suppose one option would be to partition the external drive, using one partition for backups and the other as a recovery drive. Would that work? Is that the only option?


Thanks in advance for any advice from all you Lion cubs. And Happy Easter.

-- Philip

MacBook Pro (17-inch 2.4 GHz), Mac OS X (10.7.3)
  • Shootist007 Level 6 Level 6 (16,640 points)

    Yes you need to partition that drive. then do the install again of Lion.

  • Zilacr7 Calculating status...

    Somebody tell this newbie what ALL of the above means??!! I am having a similar problem. I have a WD external drive... was working great, and all of a sudden, BAM! Stopped working! Now my mac pro does not even recognize it! I just don't get it! Please! I have VERY important files on that drive and I can't read them at all! What can I do to fix this problem??!!


    Any help is welcomed and appreciated before I take the mac to the apple store "/ Very unhappy indeed! My mac is barely even a year old!


    Thanks so much,


  • Shootist007 Level 6 Level 6 (16,640 points)

    Liza is your WD USB drive powered by only the USB port, it has no AC adapter?


    If it is one of those type drives they have been known to fail and or for some reason not get enough power from only plugging them into one USB port. to supply more power to them you may need a Y USB cable that connects to two USB ports at the same time.


    Then again if the drive has failed it may not be the Drive itself but the USB electronics in the Enclosure the drive is in. Taking the drive out of the enclosure and using a SATA or IDE to USB Adapter that has its own AC adapter to power the drive will allow you to access it and get the files off it.


    Be advised that any and all external drive should only be used as a Back Up for files that are contained on your internal drive and or on some other external drive. Making sure you have at least 2 copies of all your important files.


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