SOLVED!! I spent many hours researching this issue and tried everything in all the solutions posted here without success. Through a series of testing steps I discovered an article that said to either restart the QuickbooksDB Service (which I had tried several times) or disable QUICKBOOKS MESSENGER! What?? Apparently it wasn't shutting down properly and kept thinking that the user was the host. Not sure about all of that but my issue was solved. Just wanted to let you know.