I had this stuff happen to me as well. I was attempting to merge plugins and found out i needed files from the creation kit that were missing for some odd reason, even though my creation kit was already installed. So i just did the classic way of obtaining those files. I uninstalled the creation kit from steam and then proceeded to reinstalling. Then i noticed that my Skyrim folder was missing almost all the files and the game was basically uninstalled. Thankfully all my mods are installed through Mod Organizer so it wasn't that big of a deal, but then i realized that my configured ENB was missing that i spent loads of time messing with. When Steam deletes something its basically lost forever, even when i tried using a data recovery software the files couldn't be restored. I don't understand why Steam has to permanently delete files. Why can't steam just move the files to the recycle bin for the time being? I've just always wondered about this and i thought i'd share my story. Now i'll be reinstalling my ENB and probably fixing my skyrim setup for quite a while. :/