For years now everyone who needs backup just leaves a now-cheap ultra fast external drive continually plugged in to the back of their mac or macbook, job done.

To disable the "local" (internal drive) backups, you would just

$ tmutil disablelocal

This is gone in 10.15.2 :/

How to completely stop local time machine backups on 10.15.2 ?

  • Why do you need to? They are temporary files, and the space they use is considered as available storage by the OS.
    – benwiggy
    Commented Jan 10, 2020 at 10:03
  • hi @benwiggy - good question; but they slightly slow down your drive operations. (and for those in sensitive fields it's a slight security/privacy variable to eliminate)
    – Fattie
    Commented Jan 10, 2020 at 10:10
  • Do they? Aren't they just a bonus of copy-on-write in APFS? mac-optimization.bestreviews.net/…
    – benwiggy
    Commented Jan 10, 2020 at 10:19
  • @fattie How exactly would local backups slow down anything? Catalina requires APFS, TM on APFS is using snapshots. Regarding "sensitivity"... the data is on the HD, how is a snapshot more sensitive? Commented Jan 10, 2020 at 21:38
  • 1
    @benwiggy. This isn't true. I just deleted all local snapshots on my machine, and gained 60gb of free space.
    – Nico Burns
    Commented May 17, 2020 at 13:45

2 Answers 2


Keeping an external drive connected cleans up snapshots in 24 hours. There’s no real need to disable things in my experience, other than let the hourly backups run and prune.

I would also upgrade to 10.15.7 and then report if you have some specific issue once a day passes on the new system build.

With APFS on SSD I can’t measure any performance issue since copy on write is basically handled at full speed via non-blocking IO.

The old mechanism absolutely had a performance impact so strategic cases, disabling made an effect. If you are on a hard disk and APFS, you have much bigger performance problems in general with APFS than managing the snapshots.


FYI, try this to remove all snapshots (this won't disable it though):

tmutil thinlocalsnapshots / 1000000000 1
  • The "tmutil thinlocalsnapshots / 1000000000 1" command did nothing!
    – Ammar
    Commented Jan 20, 2023 at 10:40

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