Backup fails

in macOS edited January 2014

I stupidly deleted many old back-up off of my external harddrive.  Noe Time Machine can't do a backup because it says it has 515GB of data and I only have 499 GB of space.  My data was never this large before I deleted the files.  When I open About This Mac it says my space used is only 401GB on the internal harddrive. Something happened when I deleted the external harddrive files.  I have erased everything off of my external harddrive and now I can't even do one backup. Help!! I called Apple support but they really aren't sure how to fix the problem.


  • Reply 1 of 6
    hirohiro Posts: 2,663member

    If you want to recover that old backup, unplug it and send it off to a recovery service.  That will be expensive.


    If you just want to restart the backups from a clean slate, just reformat the backup drive from within Disk Utility.  Be extra special careful to not accidentally reformat your main drive.  Then tell Time Machine to use the newly formatted drive.


    As for sizing, incremental backups like Time Machine can get larger then the source drive since it keeps old versions of files that are changed, so that's not weird.  The other number issue is probably because of how the backup files were linked and when the delete happened the links weren't handled properly from within Time Machine.  That should fix itself with the reformat.

  • Reply 2 of 6
    hiro wrote: »
    Be extra special careful to not accidentally reformat your main drive.

    Would be impossible to format the main drive while sh/he is using it as the startup disk..... Just saying
  • Reply 3 of 6
    hirohiro Posts: 2,663member

    In theory, if the reformat was done from the startup drive.  But there are other ways to get at Disk Utility and I make no assumptions about the creativity that leads to disaster.  It is never bad advice to council against doing something catastrophic, even if you think it might not be possible.  Because you don't want to find out you underestimated Mr Murphy.

  • Reply 4 of 6

    Thanks for the info - when you say reformat the external, is that the same as erasing the external and verifying the disk through disk utility? If so we (apple support walked me thought it) did that and that's when my internal hard drive got to big to fit on the external.  I don't need to receiver the old backups, I just want to back up what I have now.

  • Reply 5 of 6
    hirohiro Posts: 2,663member

    Have a look through your hard drive to see what may be unneeded or duplicated.  This can be helpful:


    You can see what folders and files are really large.  Chances are there's something there unintended.  

  • Reply 6 of 6

    Thanks for the information. Ill give it a try

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