Update error: A snapshot is currently set to boot that is not the currently booted snapshot [solved]

macos_snapshot_fix.md

Fix for "A snapshot is currently set to boot that is not the currently booted snapshot" issue

I spent a while figuring this one out. Here is what I did to render it [Solved] on my Dad's new Sonoma iMac. (BTW: I caused this problem in the first place by enabling his nfsd service, then adding and tagging the snapshot as bootable)

1. Boot into recovery mode, open the terminal and disable SIP

   csrutil disable

2. Reboot at this point back into Recovery mode and this time open up DiskUtil

   You should now be able to see the system snapshot that is causing the issue, however you will not be able to delete it (since it is the active boot snapshot) So, instead, take careful note of the previous snapshot - it might have a name like:

   com.apple.os.update-5E4DF785AD9E60757D57924284549E29EECDBFE5942B5587D41DEAD049A903BE

3. Now exit DiskUtil and go back into Terminal, then mount the booting hard disk as rw:

   mount -uw /Volumes/Macintosh\ HD

4. Now 'tag' the official snapshot as the next bootable one:

   /System/Library/Filesystems/apfs.fs/Contents/Resources/apfs_systemsnapshot -r "SnapshotName" -v /Volumes/Macintosh\ HD

   (replace SnapshotName with the name of your snaphot. (like the one I showed)

5. Now exit the terminal and go back into DiskUtil

   Now you can view the snapshot and should be able to delete the offending one if you want to. (select it and click the minus sign at the bottom left)

6. Exit DiskUtil and go back to the terminal (last time I promise) and re-enable SIP:

   csrutil enable

7. Reboot back into MacOS and your apple sanctioned update should proceed without any errors

It wasn’t Time Machine, but it was current, apparently, because attempting to delete it in Recovery mode using Disk Utility resulted in “read-only file system” error and renaming it caused Recovery's restart to require an overlay (in-place) installation of macOS Sequoia (15.3.1). The vexing issue is still that Finder began showing 45G less available space and Disk Utility began revealing the apfs snapshot in question at the same time and only a few days ago. Thanks.

Ahh ok, that explains it. Thanks for the update.

diskutil apfs listSnapshots /disk3s1

can directly get the snapshot's name from the terminal.

You can execute

diskutil list 

to know how many disk you have in the computer.

On macOS 26 Tahoe, I was experiencing the same issue while upgrading from beta 1 to beta 2.
There were two snapshots.

• com.apple.os.~
• com.apple.bless.~

I don't exactly know what bless is, but for me, I guess the bless snapshot was selected as bootable one since it was undeletable (minus button was disabled).
Just tagged the os snapshot as the next bootable one, and problem solved.

Excellent, thanks @jhaemin good to know this works with beta mess ups also 👍

@psymonryan Thank you for the instructions.