Time Machine cannot backup due to insufficient space on local source disk

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Level 1

4 points

Time Machine cannot backup due to insufficient space on local source disk

Every time I try to backup, Time Machine is complaining about not enough space on the local disk. The external backup disk has plenty space (1 TB) and the my local Macbook drive has 2 GB space. Why does Time Machine need more than 2 GB on the local disk? How much space does it need in order to be able to backup? I never have a lot of space on the local drive, but would like to be able to backup, how can I achieve this?

The exact error message is:

Time Machine couldn’t complete the backup to “Time Machine”

Time Machine could not back up the disk “Macintosh HD - Data” because it is nearly full.

Delete some files on this disk and try again.

Currently I have BigSur 11.7.1 installed. When I search online I only find issues with space problems on the backup disk, but nothing about the local disk... strange because I cannot believe I am the only one with this problem.

MacBook Pro 13″, macOS 11.7

Posted on Nov 28, 2023 1:01 PM

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Answer 1

murphgoran Author

Level 1

4 points

Dec 5, 2023 1:20 PM in response to BDAqua

Looking at the OWC Envoy Pro mini, I realise this is not practical at all, it's just in the way when it sticks out that much, also is vulnerable that way to physical impact.

All convenient compact "plugin" external storage are flash based, and therefore too slow for my use case (not just for backing up data), and all suitable high speed drives are not flexible enough to move around, since they are much bigger and/or connected via a wire.

Finally I came up with a solution that is actually quite perfect and very simple, especially with the small compact lightweight SDDs on the market nowadays! :-D

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Answer 2

murphgoran Author

Level 1

4 points

Nov 29, 2023 11:13 AM in response to BDAqua

Well that would definitely help to make the Time Machine work again. However 30-50 GB is almost half the size of my disk, and I am using the data on it a lot. I have always worked with 2-3 GB free space, never had any problems whatsoever, just the Time Machine does not want to backup. Still would be nice to know how much space Time Machine needs, and why at all, maybe workarounds exist?

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Answer 3

BDAqua

Level 10

245,375 points

Nov 29, 2023 12:17 PM in response to murphgoran

Well, you've been quite lucky so far... Mac OS uses the free space on a Drive when the RAM is used up.

I'd get another external Drive & move some big files to it, or relocate your Home folder to an external drive.

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Answer 4

murphgoran Author

Level 1

4 points

Nov 29, 2023 1:11 PM in response to BDAqua

Yes of course I sometimes run into memory problems, but a simple logout is a relatively easy solution.

Nonetheless I would love to find an external storage that is fast enough, comparable with the speed of an internal storage, and is attached directly into my laptop (like an SD-card), so I can move around freely without the hassle of a separate drive. Suggestion very appreciated!

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Answer 5

murphgoran Author

Level 1

4 points

Nov 30, 2023 1:48 PM in response to BDAqua

Thanks, unfortunately my Mac does not support Thunderbolt yet. And this disk is still a separate one, not attached to the laptop, so not very convenient when using the laptop on your lap...

I guess some kind of memory stick, SD card would be convenient, but then again not ideal for this purpose, to move all my data from the internal disk to flash memory...

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