It can be worth trying other methods of installing the mod if one isn't working. Paradox is aware of the issues users are having with the new launcher, and have their own troubleshooting advice, so looking into that is another option. We have a full guide on how to do that here. If the above doesn't work, we'd advise doing a complete, clean re-install of Hearts of Iron IV. Now re-subscribe to your mods and proceed.Delete a file called mods_registry.json.Delete the mod folder and everything in it.Find the folder where your HoI4 saves are kept (it's probably going to be in your Documents folder, some variation on C:\Users\YourName\Documents\ParadoxInteractive\Hearts of Iron IV - once you get there, you'll see folders for 'logs', 'save games', 'mod', etc.).Unsubscribe from all HoI4 mods (yes, all of them).
