Jürgen Weissgerber wrote:yes, the problem was on April 29, 2024
I'm fairly OCD about our sessions, so what I do each day is manually export a dated session backup, like "Session_Name_5-1-2024," then "Session_Name_5-2-2024," "Session_Name_5-3-2024," and so on. We keep those in a "Color" folder on your source drive (or you could call it the "Edit" folder) just in the unlikely event we have to roll back to the previous day's session.
We also have Live Save turned on and we have the Backup turned on just for the Timeline we're working on at the moment. And that gets saved to a Backup folder on the source drive.
Jim's method of relying on the session backup can also work very well. It does pay to have a "belt and suspenders" approach to making sure you always can recall your previous work, no matter what. The Undo History does not last forever.