If you change hard drives, computers or operating systems OS you will lose everything. There is NO way to save games. I suspect some executive who doesn’t play game made an executive decision to exclude games saves.
If you buy this game, play it fast and be prepared for it to disappear when your computer breaks down. 120 hours of play gone. 5-6 hours searching how to recover game saves.
This could have been a great game.
Maybe in a few years someone will fix it.
First of all hold your guns brother and open your eyes before acting this toxic 
In game options disable Cloudsaving and from the steam client as well
Then go to C:\Program Files (x86)\Steam\userdata\folder of numbers\219990\remote\save\main
All your saves are located here and make sure you get everything from here
THen go and paste them in here
C:\Users\username\Documents\my games\Grim Dawn\save\main
Disable Steam cloud saving in the Grim Dawn options > general pane.
Welcome to the forum. Nice first post, if inaccurate. Crate doesn’t have executives, just people passionate about gaming.
The game saves automatically as you play so check the locations Darkstalix has given to see if they’re still on your hard drive assuming it’s not been corrupted by your computer breaking. There’s even a guide here on the forum for how to move Steam cloud saves to your local saves.