This morning I clicked on the Gameforge icon as usual, and an "Runes of Magic Install" began. It failed to replace some file twice. I canceled and tried again. Same thing. I couldn't play. This game is like my morning cup of coffee.
I decided to do the dreaded uninstall-and-start-over, a combat strategy that none of us really likes to deploy. In the apps and features section I found 2 RoM apps. I used File explorer to move my add-ons to a safe storage area, then uninstalled one of them. Steam opened, updated, and insisted that I log in. THen Steam deleted one copy of the game. Now I am good to go.
I am mostly adding this here in case someone else has the problem. Maybe it will help. Maybe GF and RW will find this useful also.