After a laptop crash it seems like my save has been corrupted and i cant play with it anymore.
Whenever I want to play the game says my save is uncompatible with my version as i would need a more recent version of the game to play. Basically the game doesnt let me play with my save anymore.
I tried uninstalling the game, repairing it, transfering my saves, etc... and nothing seems to work as the game still doesnt wants to let me play with my ober 140 hours save. I play on pc and with both dlcs.
Do you guys have any advice for me ?

I have the same problem : can't load the save because it is uncompatible with the current version (and I'm version 1.7.6) , and indeed, what Daworn did hasn't work for me neither.

Any solution ?

Okay I found something dude, and it worked for me

Go in your installation folder (GOG Galaxy\Games\Dead Cells). There is a folder "save".
Pick the files in (option.json and user_x.dat, x is the number of the save (0, 1, 2) ) and copy paste them elsewhere to get the backup in case there is something wrong.

Go back in the folder "Dead Cells" and go to the folder "!Downloads\!CloudSyncBackup\save"
There is the same file names.
Copy them and paste it in your "Dead Celles\saves" folder. Replace the files and launch the game.
It worked for me =)