If you go to this directory /home/ur/ursim-current/.urcaps you can find the URCaps installed in your simulator. You need to remove the URCap that is making trouble and the simulator will run again
That isn’t working, that was the first thing I tried. I had to delete “default.installation” and “default.variables”, that made it work again. Somehow I am breaking the installation by saving the feature to use.