So i created a new start date for my mod (0.1.1) but it is stuck on updating history when i try and load it up

If it's for your mod "Milleniums" you need to set a default country

If it's for your other mod, you need to assign countries and a default country

Thank you I will try this now

It now gets stuck on precalculating naval distances in the loading screen

If you run the game in debug mode, what errors do you get?

It says this: [16:01:03][countrydatabase.cpp:137]: Duplicate Country Tag - ENG

Is that the entire error log?

Yes, that is all it says

Sorry I didn't get a chance to look into this further yesterday. It seems it's because you haven't ticked the "default" checkbox on your start date.

The game needs to know which start date to pre-select, and as there isn't a start date which is set to be the default one, it crashes.

Thank you very much, it works now :)