Games Backup arghhh!!!!

Not sure what you're trying to do. Your saves and all that are online, right? If you're trying to save all the downloaded game data so you don't have to download to the second PC--because you have shitty internet, I don't know how much of a 'backup' that is, and Steam's games backup feature is both weak and not intended for the purpose you're using it for anyway. Just copy the folder for that game in SteamApps.

So I tried to make a backup of Warframe and it just did the same thing for me! Guess it could be a problem with these particular games. The backup feature in Steam has always been pretty terrible though. Even on a good day it sometimes just refuses to start backing up or ends up re-downloading the game when you try to restore the backup. I stopped using it way back when because of those problems.

It's easier to just copy the game from the SteamApps folder manually, that usually works well when moving games from one computer to another. You could also try the In-home Streaming feature. That way you'd only have to install the game once.