If you have a saved scenario that has scenario parts that come from a mod, and the mod isn't loaded, you can't start a new game at all. Instead you have to load the mod then start a new game. This can be a problem if you've subscribed to a scenario on Steam that uses a modded scenario part forcing you to load a mod that might not be compatible with the current version, as it isn't updated yet.
Edit: For context, I'm not talking about using the modded part. I'm talking about being in vanilla and just hitting New Game and happening to have a scenario saved into the scenario directory that uses something that came from a mod. The new game won't come up, and you get an error about being unable to find the modded scenario part.
Edit: For context, I'm not talking about using the modded part. I'm talking about being in vanilla and just hitting New Game and happening to have a scenario saved into the scenario directory that uses something that came from a mod. The new game won't come up, and you get an error about being unable to find the modded scenario part.