Setari: Holy crap, I never had problems with GoG Galaxy on Windows 7 but on 10... wtf man.
My Witcher 3 download has restarted 3 times. By itself. Not once has it successfully completed an install.
This is awful. Just awful. Guess I'm manually downloading from the website -_-
Not that the GoG staff cares or anything, I'm just 1 person out of a million who the client works for but whatever.
Did you update from previous OS or do a clean install? While many programs transfered without problems when my parents upgraded their Win7 desktop and Win8.1 laptop to Win10, some did not even start after the update while others had all kinds of problems. For most part, uninstalling and reinstalling the programs fixed the issues.