How safe is it to reformat one partition?

Discussion in 'OS X Yosemite (10.10)' started by Hrothgar, Nov 18, 2014.

  1. Hrothgar macrumors 6502

    Joined:
    Mar 11, 2009
    Location:
    New York
    #1
    As noted on a different thread, I seem to have developed an issue with the Time Machine partition on my external backup drive -- there is one other partition on the drive. After a few backup errors, I tried running Disk Verify, which got an error code and then Disk Repair, which got the following error code: "File System Check Exit Code 8."

    Last night I plugged the external drive into a different Mac. The second partition seems fine. But for the Time Machine partition, I got another error and this message:

    "OS X Can't Repair Disk: You can still open or copy files on the disk, but you can’t save changes to files on the disk. Back up the disk and reformat it as soon as you can."

    Before I reformat the Time Machine partition, I want to make sure that I'm not at risk (or a significant risk) of losing the data on the second partition. I expect the answer I'll get is: Back up the second partition first. However, since this is my back up disk, that would require me to buy or borrow a new drive with at least 300gb free storage. Not so easy.

    So -- should I go ahead and reformat the Time Machine partition? Or should I take the effort to back up my second partition before doing so? Or is there another fix?
     
  2. hologram macrumors 6502

    Joined:
    May 12, 2007
    #2
    It should be perfectly safe.

    That being said, there are never any absolute guarantees in life. What if you lose power in the middle of the format?

    If you have anything that can't be replaced on the second partition, you'd better back it up even if it's NOT easy.
     
  3. Hrothgar thread starter macrumors 6502

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    Mar 11, 2009
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  4. simonsi macrumors 601

    simonsi

    Joined:
    Jan 3, 2014
    Location:
    Auckland
    #4
    Not wise to be backing up one partition to another partition on the same disk if that is what you mean you have setup.

    To answer your original question, the risk is low but not zero, if you had any reasonable backup of the other partition you are not formatting then that would be fine IMHO but it sounds like you don't in which case, worst case you could lose data if you don't take a backup first.
     
  5. Hrothgar thread starter macrumors 6502

    Joined:
    Mar 11, 2009
    Location:
    New York
    #5
    I back-up my lap top drive onto the Time Machine partition on my external HD. I have a second partition on the external HD which stores a lot of old photos and duplicate music files. I have not been backing up the second "media" partition (almost all of it is located elsewhere, just not in an easily accessible place.

    I'm going to re-format the Time Machine partition on the external drive. But first I'll try to find another external HD to backup the second partition.

    I know that no drives are perfect (and I don't know if this is a drive problem or a computer/software issue), but it's annoying that I need to go out and find a backup drive for my backup drive.
     
  6. Hrothgar thread starter macrumors 6502

    Joined:
    Mar 11, 2009
    Location:
    New York
    #6
    I was able to back-up what I needed and format the problem partition. Everything seems to work fine now.
     

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