I have mac book pro mid 2015 with high sierra. I backup to time capsule network drive. Initial backs ups transferred like this.

day 1 250gb day 2 80gb day 3 60gb

It would then do small backups regularly with no issues, which corelates with my daily usage but on day 15, it started transferring 30gb+ again. So whenever I do have laptop open, it never completes transfer or backup. Latest complete backup is maybe a week ago.

I use the laptop every day, but apart from a few music album downloads, I'm not a heavy downloader.

My total space used is currently 257gb (500gb total). Only thing I can think might cause it to act up, is I have some VMs on my machine that might cause it to think it needs to transfer those images constantly. I have google drive, and icloud for offline backups.

Edit: How can I stop this from happening, and create a backup.

  • Can I suggest you edit your question to clarify exactly what your question is?
    – Monomeeth
    Oct 21, 2017 at 9:44
  • You may want exclude some folders or apps from your backup, like if you have Xcode installed, it’ll backup 10 GB, every time the app is updated.
    – Harcker
    Oct 21, 2017 at 10:13

2 Answers 2


I use the application BackupLoupe to examine my Time Machine Backups. This enables me to see what is in each backup and then set exclusions as appropriate to meet my needs.

The biggest exclusion is the folder my virtual machines are stored in. I never allow Time Machine to backup my VM's.

System Preferences > Time Machine > Options... > Exclude these items from backups:

Note: I have no affiliation with soma-zone the developer of BackupLoupe.

  • 1
    If you know terminal you can use tmutil compare to view what exactly is in the incremental backup.
    – amdyes
    Dec 19, 2018 at 6:48

Virtual Machines are a special kind. If you are not careful, they are put in a single file on the file system so any single bit written inside it will cause the whole file to have to be backed up again. I would guess this is what you see.

You can either tell Time Machine not to back up your virtual machines at all, or create a sparse disk image (which consists of a large number of individual parts) where you can move your virtual machine files to. Then MacOS only needs to back up the parts that changed which I used for a while giving a reasonable compromise.

See https://blog.fosketts.net/2015/07/22/how-to-use-mac-os-x-sparse-bundle-disk-images/ for instructions.

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