This is a situation that occurs whenever a user attempts to save a custom tire into the user.db from within an existing case file. It is a known issue that will be fixed in a future release. The workaround so that you can continue with your case requires you to restart HVE, then add any vehicle and fit it with your tire of choice. Then you can edit and save this new tire into your user.db. As long as you do not save the casefile you are working in, you can edit and save repeatedly into user.db. Once completed, simply go back into your existing cases and fit your vehicles with the tires you previously saved into the user.db.