Time Machine hasn't backed up for a week. It says "There isn't enough space," and yet there is plenty.

I'm backing up to a Western Digital My Passport with 5 TB capacity and 4.81 TB free. Time Machine correctly reports there is 4.81 TB.

I have a 1 TB hard drive on my MBP running Catalina. If I click on the options for Time Machine it says: "Estimated size of full backup: 100.51 GB."

However, when I click on the red "information" "i" next to the Latest backup, it reports that it needs 50.21 PB (yes, PB) of space. What in the world? I already have things like ~/Dropbox excluded.

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    You might review this article: macworld.com/article/3564609/… Jul 9, 2020 at 0:21
  • One file can exist in an unlimited number of locations on the disk. When this is copied to another disk, these duplicates will be split up into separate files. I'm guessing that's what is happening here - try using an app like Grand Perspective to find them and decide where to go from there. It might be something silly like a cache. Or it could just be a bug in time machine. Jul 9, 2020 at 5:37

1 Answer 1


The comments got me pointed in the right direction. In my case it seemed to be all the Python virtual environments I have. I excluded all that I could find, including ~/.pyenv/. Would be sad to lose those, but not the end of the world. I'll have everything else in source control.

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