Thanks a lot for you answer Cz-BladE.
To be honest, I'm a little bit confused with your message. First, it's a big process without internet by fiber, second : "a problem on your end", the game is already on a SSD (not the same partition that OS) and without cloud saves. So in a particular way, this issue is related to the game no?
But yeah, if I have not the choice I'll try that.