Hello,
today I did quite a few hours of work on a project. After adding two additional layouts and trying to define a print range (before exporting), Dorico became unresponsive.
This was around 17:55
Sometimes these stalls sort themselves, if I wait for a while. Not this time… A couple of times I tried to save (CMD-S) but no visible response. I had a look at my Dorico project file. It showed a timestamp of 17:30. So it seemed I had lost the last 25 Minutes…
Then I looked up the project file in the Dorico Backup folder. It also had the time stamp of 17:30. Not helpful. I left the room for half an hour, to give miracle a chance. When I returned the situation was the same - so I decided to Force Quit Dorico and redo the last 25 minutes of work.
Now, whilst relaunching Dorico, the unexpected happened. It asked me, wether I would like to recover my project - with a time stamp of 17:51, a suggestion I happily followed.
Can someone please explain, where this file version originates from, if not from the Backup folder? Is there a secret cached file somewhere?
There is a separate folder for AutoSaves in the user Dorico 4 folder. On Mac it’s
~/Library/Application Support/Steinberg/Dorico 4/AutoSaves/
Backup files are made only when you explicitly save; autosaves happen automatically.
Thank you Mark, I wasn’t aware of this distinction Auto Save / Backup. I’ll put a link to that folder to an accessible place.
Life will be calmer from now on 
Note that when you close a project, its auto-save files are moved to the Trash. The same is true at Quit.
If Dorico launches and finds projects in the auto-save folder (e.g. after a crash or force quit), then it offers them to you at restart. OTherwise, you’ll find your trash full of auto-save files.
Yes, I wouldn’t advise going rooting around in the auto-save folder yourself. There are reasons we keep it tucked away out of sight. The files in there are transitory and Dorico will delete them (move them to the trash) as soon as they are no longer required, which is when you close the corresponding project, or close the application.
Thanks Daniel, I think I have finally sussed, how the system works - it’s a good setup.