glad that worked OK for you, and many thanks for the report much appreciated.
We did a a lot of QA testing on the Recovery - I particularly like that you no longer get the scary messages about missing blocks or orphan blocks asking you what you want to do with them - now Audacity just handles all that for you.
I’ve just emailed the developer who implemented Unitary Project to ask him that question.
When the crash occurred I was doing some spectral editing and I had just selected a section of the spectrum and I used an assigned keyboard shortcut to execute the spectral edit multi-tool command. I believe I did not have an upper or lower bound on the selection so I think it attempted to execute a notch filter on the selected frequency. I have done this many times under 3.0.0 with no problems so I don’t believe it was that particular command that caused my crash. But in case you are tracking, that is what was going on.
It’s a per “action” basis, not a timer basis. Any action that modifies the project file will take a snapshot (we call it “autosave”). Several other do as well. Basically, anything you do that adds an entry to “View → History” will have created a snapshot.