@davidgh121 Hi. I’m afraid to say that even though this is rare. It seems to happen on very particular circumstances under Windows OS and the developers have not been able to find a definitive solution.
The development builds don’t do seem to do this from current reports after other improvements but, since the damage is already done, I won’t recommend you to use them right now.
Honestly I’m really sorry this happened to you. If you have at least some preview videos you exported before you could try to import them back into Pencil2D or another app to get part of your work back,
However considering all of this I’m sorry to say that if you didn’t have an additional backup copy of your file (which we always recommend regardless of animation software used) I don’t think it will be possible to recover the lost work.
I personally always save at least 100 different files out from the same project with numbers to avoid this because Ive been burnt far too many times by both commercial and free software.
Additionally I can point you to some ideas and steps you can try to do in a different thread reply I wrote as an answer the same problem for another user about a year ago, but bottom line without a backup copy, there’s really nothing we can do on our end.
I’ll also link this other reply to help you selecting a potentially different software in case you want to switch in order to make your work faster or smoother than what you could do with Pencil2D
I recommend Opentoonz (which released today a new version actually) or Krita for improved drawing.