Disable local snapshots in High Sierra with APFS

I want to disable this. I do not want any local snapshots in my ssd.

Turn off Time Machine's automatic backups. That's the only way to do it.

Local snapshots affects to the overall SSD lifespan.

There is no evidence of that, and Time Machine's local snapshots have little influence on the millions of write / erase cycles that occur just in a normal course of using a Mac.

Apple has many years of using solid state memory, in hundreds of millions of devices. There have yet to be any widespread reports of life-limited failures.

Do as you please though.

That's true in theory, but in High Sierra, all of a sudden I'm getting this: "Time Machine could not create a local snapshot to back up from because there was insufficient free space on the source volume(s)."

This seems to be a common problem under High Sierra and there is no way to turn off the local snapshots, which is the problem.

I'm trying to manually delete local snapshots with tmutil, and even though it says it deleted, the snapshot still is listed when I list the local snapshots. There appears to be a bug in the local snapshot management where High Sierra isn't deleting them un APFS.

I feel the same way about these snapshots "sudo tmutil thinLocalSnapshots / 10000000000 4" Go to terminal and copy and paste and login this will thin out a lot of these snapsots . I found that unchecking automatic updates and removing your disks slowed it down but didn't stop it ! If this continues and they don't fix this I am fuming about not being able to disable this . I want to keep my backups on an external drive where I have access to the fifes so I can delete them if I want , not in a hidden file I don't have permission to edit or even access it .I will get carbon copy cloner and disable time machine for good and wish I could delete it! "sudo tmutil disablelocal" was my go to command in terminal till they removed it.

Here's the solution (tip of the iceberg only):

This has nothing to do with local snapshots. Rather, TM had created an invisible monster file of a "backup in progress". Perhaps the backup process was interrupted for some connectivity reasons; perhaps the monster file would have disappeared when "progress" was resumed sometime in the future. (I have been away from my TimeCapsule ever since the monster file was created, so there has been no further attempt to back up properly and, perhaps, delete this (provisional?) monster file in the process.)

Deleting the monster file - indeed the entire "backup" folder contained in the (invisible) "Volumes" folder at the top of my HD - restored my free memory. The deletion can be performed very simply in the Finder via the trash; just make invisible files visible first by typing shift-cmd-period once the appropriate window is open. (Typing this again toggles visibility back off.)

And, yes, I did speak to Apple Support and hope this will get reported.

The snapshots are deleted as space is needed. There is no real advantage to disabling them or turning off Time Machine. See the last section of this article.

About Time Machine local snapshots - Apple Support

And to directly answer your question, in High Sierra you can no longer ONLY disable local snapshots. You can, however, turn of automatic backups. Then whenever you want to do a backup on your external Time Machine drive, make sure it's connected then click the Time Machine icon and select Backup Now. Simple.

In APFS the "local snapshots" aren't exactly snapshots -- they're file states. Because APFS doesn't write new copies of modified files, but instead appends blocks, the local "snapshot" is really just a pointer to a previous file state with a different block map.

In other words, these snapshots aren't occupying any additional space in APFS, so there's no "hidden file" to look for and delete!

That’s not (always) true.

TM local snapshots often occupies large SSD space, and you can’t do anything.

Try the following: if you have a 100 GB folder and you want to copy to your Mac which only has 90 GB free space (AND the local snapshot occupies cca 30 GB!) you can’t do that.

Simply try it if you don’t believe me!

If you run a Daisydisk, you can see the so called system files.

Try run these terminal command:

sudo tmutil listlocalsnapshots /

Here is the detailed steps to reclaim you SSD space - unfortunately this is only a temporal solution 😟

Solution: Reclaim storage back from "System" | MacRumors Forums

Best wishes,

Zsolt from Hungary

Under 10.13 (required for APFS), this should be included in the system's tracked 'Purgeable Space' now. My understanding of that command is that in APFS you're simply forcing a purge that might otherwise be unnecessary.

kaczurzsolt wrote:

That’s not (always) true.

TM local snapshots often occupies large SSD space, and you can’t do anything.

Try the following: if you have a 100 GB folder and you want to copy to your Mac which only has 90 GB free space (AND the local snapshot occupies cca 30 GB!) you can’t do that.

Simply try it if you don’t believe me!

If you run a Daisydisk, you can see the so called system files.

Try run these terminal command:

sudo tmutil listlocalsnapshots /

Here is the detailed steps to reclaim you SSD space - unfortunately this is only a temporal solution 😟

Solution: Reclaim storage back from "System" | MacRumors Forums

Best wishes,

Zsolt from Hungary

There was a bug among my snapshots

this is the only thing that fixed it

I lost nearly half of my 512GB of disc space to local snapshots overnight, or so it seems. It started with Time Machine reporting that it was backing up "281GB of 271GB", where 271GB was indeed the total of disc space I was then using. Next morning, the system alerted me that I was running out of disc space, and making recommendations as to what to delete. (As explained elsewhere, the folder sizes shown in the Finder still add up to something like 270GB. But System Info under "About this Mac" reports "system" use of 238GB, where the actual use as reported by the Finder is closer to 10GB.) I'm now down to, ostensibly, 12 GB of free memory - 3 days after turning off automatic backups, and beginning to panic slightly.

Any suggestions of what to do?

My suggestion is you call Apple support ( 1-800-692-7753 ) and insist on speaking with a senior advisor because this is a bug in the High Sierra operating system which the senior advisor will report . Don't correct this on your own because this report will support an update to High Sierra and you can be one of the hero's to getting this much needed fix to the macOS .

An APFS snapshot is done with copy-on-write and tracking of allocated blocks. That means that very little is written to create one, just enough to account for multiple references to metadata and storage. Because there is very little writing involved, there should be very little wear (esp. compared to local snapshots before High Sierra!). And they should be very quick, almost instant.

A snapshot is not free, though; as the current filesystem diverges from the snapshot, it uses more space. In the extreme, it could use as much space as if it were a regular copy (i.e. once every block was different between the snapshot and the base filesystem).

The snapshots do mean that less free space is available than otherwise would be; but the Time Machine snapshots are supposed to be automatically deleted. If you sometimes run very full, that could be a problem; otherwise, they're useful and much cheaper in time, CPU, battery, wear, etc. than Time Machine snapshots prior to APFS and High Sierra.

I use Growl and HardwareGrowler; Growl can be given an AppleScript to do automatic actions based on certain notifications, and HardwareGrowler generates notifications of disk mount or eject, power changing from AC to battery, etc. My script would disable Time Machine and eject the backup disk when AC power was removed. It also disabled local snapshots, regardless, since I didn't want them. (It also enabled Time Machine when the external backup disk was again mounted.) Given that "tmutil disablelocal" no longer works, I should remove that from my script. Other than that, I don't guess I'll care too much.

Supposedly, OS updates (the minor ones that only need one reboot) may also create snapshots...not a bad idea IMO, since apparently one can always boot the Recovery partition and restore from one of those if needed. I wouldn't want to turn _that_ off, even if I could stop the regular Time Machine snapshots from happening.

There is a small problem. A lot of apps don't recognize the "purgable" files and therefore thinks that there is no avaible space on the drive for some operations. For people who might need some more drivespace to install stuff, snapshots might get in the way. For example, bootcamp instalations don't recgnize that here is purgable space, and can't make big partitions because of that, even if you free space. You have to wait hours, maybe days to have that space back actually instead of a single backup before the operation. It's a hassle sometimes.