So I installed my GTA V onto my hard drive I got, it installed just fine. It made a steam library on it and everything, Plus I've been using it for a few weeks now. The game would run fine and I could install mods and us them just fine as well. But today I woke up and was greeted to an error message. I tried to launch GTA V and it said I needed to install the game first. This happens sometimes when I plug the hard drive in after I turn the computer on, so I just restarted the computer and then launched the game. However once again it said I needed to install the game. I restarted it multiple times and it did not work. I decided I would launch it from the exe in the hard drive itself. That is when I was greeted with the error message. "ERR_NO_STEAM". So I went to steam to make sure it was running. And on steam it said I didn't have GTA V installed either. Its almost like steam has forgotten that the game is installed on my hard drive, like steam has just neglected its existence. Which made me think that the game in my hard drive somehow unlinked its self from steam. Is that possible? Is there a way to fix this? And preferably not just uninstall the game and reinstall because how do I know it wont just happen again. so....
1 - Is this scenario even possible?
2 - What caused it to happen?
3 - How can I fix it (And ensure it wont happen again)
And ideas would be greatly appreciated,
thanks.