I know you can't fix issues with bugs in games using mods, but this happens before mods are even loaded. Since it is the launcher failing to load, I don't think the mods have anything directly to do with this (since they aren't even loaded until you launch the game itself.)
100% of the time if there is absolutely *any* mod in the mod folder besides the base mods, the launcher will fail to open. Remove all extra mods and it works just fine. Add any mod, and it crashes. I feel this is a bug with the launcher - something about mods being in that folder makes it not work.
100% of the time if there is absolutely *any* mod in the mod folder besides the base mods, the launcher will fail to open. Remove all extra mods and it works just fine. Add any mod, and it crashes. I feel this is a bug with the launcher - something about mods being in that folder makes it not work.