In which file does something like that reside, and how do I edit it? I'm looking for a different method Steam must have the list of installed games stored somewhere.
Then you shut down Steam, move the game back and resume the download, and Steam HOPEFULLY recognizes the game and everything is great again, except you lost four hours moving 150GB around like an idiot. One method I'm thinking of is to move the game to another drive (if you own one) and then start the download again. However, since the game takes over half of the size of the SSD, I cannot make room to have enough room to install it twice, not to mentioned I barely managed to make enough space to install it once. Now, Steam gets screwed in some way and no longer detects your game as installed. It's a large game, full install takes up over 152GB. You install Middle Earth: SoW on your 256GB SSD.
But before Steam even attempts to install/detect a game, it will first check if you have enough of free room on the storage device you're trying to install the game to. I know that if you just run the install with the game present Steam does all the work for you.
