I have a MacBook Pro with Snow Leopard and a Time Capsule. In the last few days every backup took over 100GB of data. I don't know if there is some issue with permissions or something similar, but to be sure I removed all the old backups and reformatted the Time Capsule disk. I've also run filesystem checks and permission checks on my MBP disk using the installation disk.

Then I've restarted backup from scratch, the first backup took 160GB and for a few days following backups has worked fine (with a decent quantity of data for each run).

Now after some days I started my MBP and the backup is still in progress, when it was started it says that it needs to backup about 40GB of data (which obviously is not true) and while running the limit is increasing constantly, currently is at 95GB and it continue to grow.

I suspect that there could be some hardware issue with Time Capsule, but not sure.

Any hint to solve this issue?

  • 1
    Is there anything particular about the data you're backing up? i.e., Virtual hard drives (from VMware or Parallels), lots of videos, movies or podcasts, etc. Even the slightest change to a large file will cause the file to be backed up as a different version and thus, increasing your total backup size. Also, do you have additional Mac partitions? Time Machine will back up every partition that is Mac-friendly (i.e., not a Boot Camp partition). Aug 16, 2011 at 14:56
  • Do you have any virtual machines running in Parallels, VMWare Fusion or similar?
    – Mike Scott
    Aug 16, 2011 at 14:58
  • 2
    A tool like BackupLoupe may show you that indeed, some files are taking space each backup and driving the estimate higher (TimeMachine does over estimate the space needed - focus on the space used which is what you can control directly). Rebooting your mac in safe mode will ensure the filesystem does a better job of estimating what has really changed. Kick off a backup before apps start the next normal boot after the safe boot.
    – bmike
    Aug 16, 2011 at 15:01
  • Does this question cover the same ground as your issue? - apple.stackexchange.com/questions/17065/…
    – bmike
    Aug 16, 2011 at 15:03
  • @ChristianCorrea and Mike Scott: I have VMWare fusion installed, but not running. Moreover I've excluded VM images from TM backup plus I haven't started VMWare since the TimeCapsule disk reformat.
    – Fabio
    Aug 16, 2011 at 15:09

1 Answer 1


Take a look at BackupLoupe:


The blurb on the website describes what it can do far more eloquently than I can, but to summarise it's commercial software that you can evaluate for free and then pay for if you with to use it. Once you have determined which backup intervals or which files are taking up more space than you wish, you can delete files across all backups or delete snapshots as needed to maintain storage space per your requirements and preference.

  • Seems interesting, I'm trying it.
    – Fabio
    Aug 16, 2011 at 14:30
  • I should amend my answer, it's not donationware, but is a commercial product, however there are no demo restrictions other than your own honesty: "We don't believe in copy protection. We do believe in honest customers. We don’t spend time implementing some sort of registration or online activation scheme. Our focus is on development of applications that work for you. As a consequence, you will not receive a serial number or license file. Despite our attitude towards copy protection and the low price tag of our software, this is not donation ware. We provide commercial products."
    – stuffe
    Aug 16, 2011 at 14:34
  • I've changed my backup disk from Time Capsule to an external NAS and now everything works. However your answer was very useful. Thanks.
    – Fabio
    Nov 18, 2011 at 14:00
  • How does this answer the question of why Time Machine backs up so much?
    – jvriesem
    May 5, 2017 at 16:48
  • It tells you what is being backed up, so you can work out why the number might be large, e.g. Is it backing up a virtual machine disk image from a running VM, and thus re backing up the entire file every hour, for example
    – stuffe
    May 5, 2017 at 22:20

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