Steam thinks game is Uninstalled when it Isn't

Steam reports the game as Uninstalled (or, NOT installed)

But the game has never been touched since I last closed the game a few hours ago:

I don’t even know how this happened. Any insight to why this would happen suddenly? Is there any way to recover?

did you try verifying game files?

That option is greyed out.

It won’t let me do it.

try following this, it seems like this happens pretty frequently:

It won’t let me try reinstalling the game because there’s not enough space, and I can’t make Steam recognize the game by adding a folder because I can’t add to the same one and the default folder cannot be removed. I’m going to try moving the game somewhere else on the disk and name it like a steam folder would.

Edit: It won’t let me. I cannot make Steam recognize the game with what you sent me.

I’m just going to reinstall the game, like it says in the guide there. Thanks for the help, though!