Can't save project After effects 24.4.1

Build:

MacBook Pro 16inch 2023

M2 Max

96GB memory

macOS Ventura 13.0

Problem:

I cannot save a project I've been working on for a few days and saved fine 2 days ago.

I have tried "save"

"save as"

"save a copy" etc etc

I've tried saving to an external hard drive

Saving to a different external hard drive

Saving to dektop.

It gives every appearance of having worked but no new or updated file appears.

If I try to close project or quit after effects and respond "save" to the question "Save changes before closing"? it goes through the motions but does not quit or close the project and no updated file is on my hard drive.

I am using the latest version, have uninstalled and reinstalled, restarted the machine, unplugged the external monitor, deleted preferences, given full disk access, tried safe mode. Nothing is working..

Any help much appreciated