Thanks in advance.

Your saves should be located in:
C:\Users\[USER]\AppData\Roaming\HelloGames\NMS\DefaultUser

you will need to use the save game decoder going from steam to GOG -

https://www.reddit.com/r/NoMansSkyMods/comments/4yjft9/no_mans_save_save_encryption_and_decryption_exe/

basically the saves are encrypted to your steam profile (the username and string of numbers in the save folder) decrypt all the files with that program, then move them to DefaultUser (for GOG) and recrypt them, you will be good

Sorry to necro an old thread, but what about from windows 10 store? Playing it on game pass and want to buy it on GOG. I want to wait for a sale but don't want to stop playing because it's so good! Lol.

Anyway, how do I find the save file for a windows store game?

Search for a directory with files named mf_saveX.hg and saveX.hg where X is 1-10 or missing. It's probably under a HelloGames directory but Microsoft so who knows. ;-)

Hello did this worked for you?

I'm in the same situation now that I got that 1euro 3 months game pass sale but I really don't feel 3 months are enough for this game and I want to buy it on gog