How do i do this? It's pretty easy to do in steam but there are no clear directions on how to do it in GOG.

Plugin new hard drive, run installers. I mean you could go through the process of copying from one drive to another, scanning with galaxy, making sure all dependancies are present, or you could just do it the simple way.

I don't know about using the client which I presume you are using else you wouldn't be asking this question.

But if you do not use the client and use the completely DRM-free aka offline installers, just re install the game with them to wherever you want...no need to be online or anything.

I'm not clear on what you mean by moving a game to another hard drive. But as others have said, the offline installers let you pick an install location, you just install the game and select where you want it to install.

If you're talking about moving a game already installed to another drive, then that's different, as there are dependencies other than just a directory. It's probably not worth the trouble though. I would just reinstall to the other drive.

Thank you all for the help! It was quite easy to transfer the game into another unit as the process was simply to uninstall it and then redirect it into the designated unit.