Can't seem to mount a snapshot

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Level 1

24 points

Can't seem to mount a snapshot

I'm running the latest Mojave. I create a snapshot with:

$ tmutil localsnapshot
Created local snapshot with date: 2020-08-04-150521

Then I want to mount it:

$ sudo mkdir /private/tmp/snap
$ sudo mount_apfs -o rdonly,noatime,nobrowse -s com.apple.TimeMachine.2020-08-04-150521 / /private/tmp/snap
mount_apfs: mount: Operation not permitted

I've tried various options, other paths, etc., and can't get it to mount, I always get the Operation not permitted (unless a snapshot of the given name doesn't exist, in which case mount_apfs fails *silently*. Grrrr)

iMac 27″, macOS 10.14

Posted on Aug 4, 2020 3:26 PM

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Answer 1

Top-ranking reply

benjamindines

Level 1

14 points

Sep 1, 2020 11:45 PM in response to blmatthews

I think brenden dv might have just failed the Turing Test.

Anyway, after scouring Google for the answer to the same problem, I found a post where someone suggested making sure Terminal.app is allowed "Full Disk Access" in the OS Privacy Settings. Sure enough that worked.

Credit given to this page: https://forum.duplicacy.com/t/error-error-vss-create-error-while-mounting-snapshot-exit-status-73/4061

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Answer 2

blmatthews Author

Level 1

24 points

Sep 2, 2020 10:05 AM in response to benjamindines

Ah, thank you! I use iTerm, but once I gave it Full Disk Access, the mount worked fine.

And thank you Apple for providing helpful and informative error messages and documenting those error messages in the man pages so I could quickly diagnose and fix my problem. Oh, wait, you did none of that.

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Answer 3

HWTech

Level 9

68,636 points

Aug 7, 2020 5:58 PM in response to blmatthews

FYI, here is an article on how to mount an APFS snapshot and except for the extra options seems to be what you are doing:

https://derflounder.wordpress.com/2019/02/23/mounting-time-machine-local-snapshots-as-read-only-volumes

Try the command without all those options and try changing the mount point to a folder within your user folder where you know you have the correct permissions. The comments in that article mention some differences with Catalina so perhaps a Mojave update changed the behavior to match Catalina.

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Answer 4

blmatthews Author

Level 1

24 points

Sep 3, 2020 6:53 PM in response to HWTech

Yes, the error message is poor (or nonexistent), but even if in the mount_apfs man page they listed the 5 (or however many) circumstances an Operation not permitted could occur, and one was a lack of Full Disk Access, it would have saved me a lot of time, and saved everyone that was nice enough to respond some time. Unfortunately the manual pages for a lot of Apple-specific command line tools are weak at best.

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Answer 5

brenden dv

Community Specialist

Aug 7, 2020 7:40 AM in response to blmatthews

Hello blmatthews,

We understand you're having an issue with mounting a snapshot on your Mac with Mojave, and we'd like to help.

We've located this article that goes into detail about that:

If you can't back up or restore your Mac using Time Machine

Restore items backed up with Time Machine on Mac

Cheers!

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Answer 6

brenden dv

Community Specialist

Aug 7, 2020 2:09 PM in response to blmatthews

Hi blmatthews,

We apologize for the misunderstanding. We'd like to investigate this with you, and ensure we explore every opportunity to help. Could you please provide more details about what you're trying to accomplish?

If you prefer to work directly with our Mac experts, please contact Apple for further assistance:

Contact Apple Support

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Answer 7

blmatthews Author

Level 1

24 points

Aug 8, 2020 10:38 AM in response to HWTech

I think I'd done all the things you suggest when initially trying to get it to work, but I went back and did it all again more systematically:

$ tmutil localsnapshot
Created local snapshot with date: 2020-08-08-101011
$ mkdir ~/snap
$ mount_apfs -s com.apple.TimeMachine.2020-08-08-101011 / ~/snap
mount_apfs: mount: Operation not permitted
$ sudo -s
Password:
# tmutil localsnapshot
Created local snapshot with date: 2020-08-08-101147
# mkdir /tmp/snap
# mount_apfs -s com.apple.TimeMachine.2020-08-08-101147 / /tmp/snap
mount_apfs: mount: Operation not permitted

I've also tried using an existing snapshot created by Time Machine (in case one I create is somehow different), using .local on the end of the snapshot (which results in the silent failure I noted originally, because on Mojave that's not a valid snapshot name), specifying /sbin/mount_apfs (although bash says that's where it is when I just use mount_apfs) and instead of mounting / trying various subdirectories, including my home directory. All (except the silent failure with an invalid snapshot name) result in Operation not permitted from mount.

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Answer 8

HWTech

Level 9

68,636 points

Sep 2, 2020 10:16 AM in response to blmatthews

Thanks for confirming @benjamindines' suggestion. Good job @benjamindines! I need to remember Full Disk Access.

I agree Apple has some of the most cryptic error messages around. I guess I'm spoiled with Linux where many times the error message will actually have the solution displayed in the message. Sometimes it is the little details.

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Answer 9

blmatthews Author

Level 1

24 points

Aug 7, 2020 11:24 AM in response to brenden dv

Neither of those say anything about mounting a snapshot at all, why do you think they apply to my question?

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Can't seem to mount a snapshot

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