If you have had the job open since Friday and have not manually saved it yourself then you really have no-one to blame but yourself.
Don't rely on auto-save.
Save every couple of hours or when you have done something important that you don't want to re-do.
And if it is just a design process that you are not sure that you want to keep then save-as with a new name and save-as with the real name when you are happy with the design.
If your disc was reporting that it was full then maybe that is why Archicad could not save the auto-save files.
I have no real idea why this would be the case that your disc was full but maybe it has to do that you have left your machine running for a long time without shutting your applications off.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11