Problem with my save

Hi ! I'll start by saying, I'm sorry for my english, I'm french so I try my best 😅

For the last couple of days I got some issues with saving my game and I'm a little lost.
Last time I played, I tried to save and I got a error notification. After a couple tries, I just clicked "save as..." ("enregistrer sous" en français) and ignored the issue, thinking maybe I nedded to update my mods.

Well, that's what I did today, everything is up to date, but impossible to play on my save... I can save, the document is in the file, but I can't open it. I'm stuck with the save pre-bug... I checked and this save is the only one with this issues, none of my other saves seems to have trouble...
I can't "recover" or "get back" (how is it in english ? The little diskette ?) I click, it load and then nothing...

It's an old save too, 6 generations of the same family, I would be devastated if I lost everything...

What can I do ?