light487: So when I first downloaded the game, I had it in Galaxy client and the client preloaded and installed the game to my C drive. I wanted it on my S drive, which is my SSD. So I simply moved the entire folder structure to my S drive. Of course you can't get the patcher or Galaxy to fully understand that move. Even though Galaxy was saying that it found all the files, it wasn't really and was looking in the old install folder. This is easily fixed by editing some Registry settings:

For me it was located here:

Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\GOG.com\Games\1207664643

Change the following registry entries:

EXE
LAUNCHCOMMAND
PATH
uninstallCommand
WORKINGDIR

For example, LAUNCHCOMMAND originally had "C:\GOG Games\The Witcher 3 Wild Hunt\bin\x64\witcher3.exe" and because I kept the same parent folder structure on my S drive, it was a simple matter of changing it to "S:\GOG Games\The Witcher 3 Wild Hunt\bin\x64\witcher3.exe".

The other folders are just for save games and the start menu links. You will need to change the shortcuts in the start menu and your desktop manually.

Once I changed these registry settings to the correct drive, the patch worked flawlessly and the game ran immediately without any problems. I've not yet tried launching from Galaxy but I don't see why it wouldn't now properly detect it.

Dreamo: Actually, you can simply scan and import new folders to Galaxy by pressing the "+" icon on the left corner and then choosing Scan and Import Folders. And done. See attached screen shot.