Hello,

I'm making a backup hard drive and plan to download all of the games in my library. But I don't want to install every one of them to find out if a file was corrupted.

Is there a way to check the files without installing the game?

you can point Galaxy to the files and ask it to verity, which will [in effect] install the game without needing to download much.but this does install the game to your system & it also needs a small interent just to check your files against the internet list to see what is missing

there are also cross platfrom issues like for example old system is Windows 10 32 bit installer but new computr is Windows 10 64 bit or one Amd and the other Intel... these cases sometimes need 3rd party system files that Gog does not check because they just assume dirrect X is installed on both systems