Disk space vanishing

sub.one wrote:

I just updated from Big Sur to Monterey. Before the update I had about 167 GB of free disk space with no local snapshot (according to tmutil). After the update I had about 164 GB of free disk space and I deleted the local snapshot increasing the free disk space to a 194 GB. Then I rebooted the system and the free disk space dropped back to 164 GB.

So free disk space:

Before Update, no snapshots exists: 167 GB

After Update, 1 snapshot exists: 164 GB

After Update, snapshot deleted: 194 GB

Reboot: 164 GB

Can anyone explain this mess? I mean dynamic allocation...but seriously? I deleted something and by 'magic' the space vanished again.

Why micro-manage snapshots...

Try plugging in your Time machine backup and let it run...

Have you rebooted more than once since the upgrade?

Is this a one off analysis of your situation are have you used the new macOS for a couple weeks and the problem persist...(?)

Local Snapshots are allocated on the source volume. If you want to restore from Local Snapshots follow the instructions, Recover all your files on Mac however choose the source volume not Time Machine backup disk.

https://support.apple.com/en-us/HT204015

About Time Machine local snapshots - Apple Support