I spent 30 minutes redacting a document, removing metadata, and when I hit save---poof! it disappeared. I could quit.
Document disappeared completely. The most bizarre disappearance of a 30 minute project EVER.
Acrobat has inbuilt mechanism for Auto-save to recover files in case of a crash.
Requesting you to please let us know if you have received the prompt to recover your file on relaunch.
The default time settings of Auto save are present & modifiable at-