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Time Machine difficulties!

482 Views 9 Replies Latest reply: Dec 19, 2012 2:39 PM by Linc Davis RSS
elliswicks Calculating status...
Currently Being Moderated
Dec 13, 2012 6:17 AM

Hi guys,

I've been using my Seagate Portable Media 500GB external hard drive for Time Machine on Mountain Lion.

Time Machine's backup failed, with the message "Unable to complete backup. An error occurred while creating the backup folder."

Using Disk Utility, I verified the disk, which asked me to repair it. On trying to repair it, I received the message "Couldn't unmount disk". I received this message also when trying to Erase or Partition the drive.

I then booted into the Recovery HD and successfully repaired the disk started Time Machine all over again.


After a couple of days, the same thing happened again, it seems this is a temporary solution.


I have tried Total Resets of TM, which had no effect.


I have no other hard drives plugged into TM and the hard drive is formatted Mac OS Extended (Journaled).

I've also tried using a new power cable for the drive and I'm having the same results.


Any advice on what I can do next would be great!


iMac (21.5-inch Mid 2011), OS X Mountain Lion (10.8.2)
  • rkaufmann87 Level 8 Level 8 (40,500 points)
    Currently Being Moderated
    Dec 13, 2012 6:21 AM (in response to elliswicks)

    Please carefully look over Pondini's Time Machine Troubleshooting & Time Machine FAQs for your answers.

  • Radiation Mac Level 5 Level 5 (4,630 points)
    Currently Being Moderated
    Dec 13, 2012 6:30 AM (in response to elliswicks)

    You should find this very useful:




  • Linc Davis Level 10 Level 10 (107,430 points)
    Currently Being Moderated
    Dec 13, 2012 8:54 AM (in response to elliswicks)

    If you have more than one user account, these instructions must be carried out as an administrator.

    Launch the Console application in any of the following ways:

    ☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

    ☞ In the Finder, select Go Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

    ☞ Open LaunchPad. Click Utilities, then Console in the icon grid.

    Make sure the title of the Console window is All Messages. If it isn't, select All Messages from the SYSTEM LOG QUERIES menu on the left.

    Enter the word "Starting" (without the quotes) in the String Matching text field. You should now see log messages with the words "Starting * backup," where * represents any of the words "automatic," "manual," or "standard." Note the timestamp of the last such message from a failed backup. Clear the text field and scroll back in the log to that time. Post the messages timestamped from then until the end of the backup, or the end of the log if that's not clear.

    Post the log text, please, not a screenshot. If there are runs of repeated messages, post only one example of each. Don't post many repetitions of the same message.

    When posting a log extract, be selective. Don't post more than is requested.

    Please do not indiscriminately dump thousands of lines from the log into a message.


    Some personal information, such as the names of your files, may be included — edit that out, too, but don’t remove the context.

  • Linc Davis Level 10 Level 10 (107,430 points)
    Currently Being Moderated
    Dec 16, 2012 8:26 AM (in response to elliswicks)

    Your backup drive is malfunctioning. Replace it immediately.

  • Linc Davis Level 10 Level 10 (107,430 points)
    Currently Being Moderated
    Dec 16, 2012 3:08 PM (in response to elliswicks)

    There are essentially four possible points of failure:


    1. The data port on your Mac, or some other internal component.
    2. The data cable to the external hard drive.
    3. The drive enclosure.
    4. The drive mechanism.


    You can try to localize the failure to one of those components by switching them around. For example, you can plug the cable into a different port on the Mac; you can use another cable; you can test with another drive; and so on. You can also buy an inexpensive drive dock or enclosure for about $50 or less and put the drive mechanism into it. That may not solve your problem, however.


    If you're asking for some kind of magic button you can push to solve this problem at no cost and with no effort, there isn't one.

  • Linc Davis Level 10 Level 10 (107,430 points)
    Currently Being Moderated
    Dec 19, 2012 2:39 PM (in response to elliswicks)

    You might be able to salvage the mechanism of your existing by drive by removing it from the enclosure and putting in a USB/FireWire dock, such as you can find on Amazon, for example. There's one called "Voyager" that's relatively cheap. If the drive doesn't work, buy another bare hard drive. I don't have a specific recommendation, but avoid drives marketed as "eco" or "green," as they tend not to work reliably with Time Machine. Before you do any of that, make sure the problem isn't just a bad cable.


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