Tahoe endlessly consumes all free space, 270 GB, on MacBook Pro

[SeamusDeMora]

I just bought an obscenely expensive M5 MBP w/ 4TB drive. I've not had any issues with running out of space (yet :| ), but I've had lots of other problems - each one taking from 15 minutes to several hours to research, and finally correct. Apple remains one of the WORST tech companies for usable documentation... using macOS is like being dropped into the middle of the remotest area of the Amazon jungle without so much as a compass to guide you.

However: I did very much enjoy reading the post from "MarineBand5524"! Thank you, sir!

I have a follow-up question: I do my Time Machine backups to a NAS. I very much like the idea of disabling "local" snapshots. However I do wonder just what Apple's purpose (other than possibly fuzzy thinking) was for even creating "local" snapshots? Or, forget "Apple's purpose", and explain the utility of "local" snapshots... Does anyone know?

I'd **LOVE** to delete these "local" backups, but always nervous about mucking around with little or no knowledge of the design or logic that caused them to be created in the first place.

 

[Mike Boreham]

@SeamusDeMora Local snapshots are extremely useful to me. Two main uses:

1.The local TM snapshots are by far the fastest way of rolling back the whole machine to a previous state and I have used them for this several times when I have taken a misstep and realised it is much quicker to roll back than undo the misstep. And much quicker than EACAS and restore from TM backup. It seems a little known and little used method. Most people treat them as a nuisance to be deleted as they can be the cause of feee space fluctuations. Of course the TM local snapshots can only roll back up to 24 hrs, but CCC snapshots (which are the same) can be preserved for longer. However since Big Sur (reference) you can't use a local snapshot to roll back across a macOS update unfortunately as the snapshot is only of the -Data volume. TM Local snapshots are not subject to any exclusions applied to the regular TM backups.

2.If you are travelling and don't connect the TM backup volume, you can recover deleted files from the TM local backups on the boot volume.

I don't believe there is a way of disabling them, but it should not be necessary as the space used is not supposed to be treated as used space by Finder, but this does not always happen and is the cause of apparent big fluctuations of free space and free space not being returned when a large file is deleted. I sometimes delete the local snapshots but mostly I don't and the Finder free space sorts itself out.

I agree about Apple documentation. I cant find any Apple document about rolling back the whole machine, only third party ones like this one. However that link is wrong because it says you can roll back the macOS version by this method which is no longer true. Apple does document the second use above here.

You may find this article helpful: Why all the Snapshots?

 

[jido]

Beware of Xcode caches too! They can grow quickly.

 

[Ben J.]

I'd **LOVE** to delete these "local" backups, but always nervous about mucking around with little or no knowledge of the design or logic that caused them to be created in the first place.

You can delete snapshots in Disk Utilities:

View APFS snapshots in Disk Utility on Mac

In Disk Utility on Mac, view a list of APFS snapshots, copy information about the snapshots, and delete them.

support.apple.com

Totally safe - but of course, you'll lose the ability to restore older, deleted files and the ability to roll back the drive to an earlier state. You might start by deleting the oldest snapshots first, and maybe f.ex keep those from the last month.

This is the basics of snapshots:
When you drag a file to the trash and empty the trash - if that file is present in any snapshot, it will stay on disk and take up space, even if it cannot be seen in Finder or anywhere else. That way Time machine will be able to restore it if needed.

 

[auxbuss]

I'd **LOVE** to delete these "local" backups, but always nervous about mucking around with little or no knowledge of the design or logic that caused them to be created in the first place.

I only run Time Machine once a week or before a macOS update. I *always* delete the local snapshot afterwards. I've never encountered a problem restoring files.

 

[2xHorn]

I have this curious behavior on a much smaller scale. I'm acutely aware of disk space because I have been using computers so long that I remember when it was at a premium, therefore, I tend to try to be very "hygienic" (or maybe psychotic) about it. I'm a bit of a nutcase about charging my phone, too, because I remember when batteries were only good for a couple of hours.

Also, I just got a refurb M4 MBA. I didn't really NEED it, because my 2017 MBP is still serving, but looking into the NEO brought it to my attention that the lowest spec MBA was soon to be over $1000. So, I got a 256GB. The old MBP has 128GB and it is serving, but I wasn't sure how Tahoe was going to utilize space and was unsure if I would regret 256.

So, I was keeping a "weather eye" on disk space on the new machine.

After booting the new one and transferring data from the MBP using Time Machine, used space crept as high as 80GB, 10 or so more than used on the MBP. But that receded over a day or two to the 70s and then 60s, so I guess garbage collection in a fresh "install."

I had Time Machine set to backup daily, I believe, even though I only plug in an external drive about once a week to do the actual backup. This was creating a bunch of snapshots, and I guess would have on Ventura on the MBP as well, but it never caused reported used disk space to vary much.

The snapshots enable Time Machine, when opened, to show a bunch of local backups where you can find accidentally deleted files and the like without having to plug in an external drive. Cool. I have never or only very very sparingly made use of this in 15 or so years of Apple computing, so I deleted all snapshots and changed TM to manual backup only. So, it makes one snapshot every time I actually back it up. Once that snapshot is made, it seems like it initially has no impact on disk used/free, but the longer it sits there, it starts to impact reported disk usage. Or maybe that's an illusion and it's something else. Anyway, I go ahead and delete that snapshot after a day or so of "observation."

For better or worse, I use Maintenance to clean up the machine periodically. I tend to do it before the weekly backup to attempt to minimize the amount of crud subject to backup. After running Maintenance, disk used retreats into the high 50s and then over the next week crawls up to the high 60s and seems perhaps to level off there. Maybe it would keep creeping up if I didn't do the weekly Maintenance and backup. Not sure.

In the grand scheme +/-10GB is no big deal. It is weird to see it fluctuate that much. I do wonder how much worse it would get if I didn't do as described above, but my sense is that it levels off at some point.

For reference, my most used applications are Firefox, Mail, and LibreOffice. I periodically dump browser history and cache and occasionally cookies (remember, disk space psycho). I do not have AI or Siri enabled.

 

[boppin]

Hi,

Remember that the graphics in "About this Mac" does not work properly for years. Please use Finder instead.