perhaps you should verify local game files

If you can still build things that would be an autoresolve loop. The AI invades another AI faction and for some reason gets stuck when trying to autoresolve the battle. There isn't much you can do but load an earlier save and hope the invasion fleet isn't already in transit in case it's consistently freezing. You can potentially invade the planet/faction yourself and prevent them from meeting or otherwise do something that causes the invading faction to do something else but that requires knowing where the battle is taking place and between which factions.

Originally posted by Lord Admiral Daniel Phillips:

If you can still build things that would be an autoresolve loop. The AI invades another AI faction and for some reason gets stuck when trying to autoresolve the battle. There isn't much you can do but load an earlier save and hope the invasion fleet isn't already in transit in case it's consistently freezing. You can potentially invade the planet/faction yourself and prevent them from meeting or otherwise do something that causes the invading faction to do something else but that requires knowing where the battle is taking place and between which factions.

Thanks, hope this ♥♥♥♥ will fix soon

Originally posted by 2 vs 8:

Thanks, hope this ♥♥♥♥ will fix soon

As far as I'm aware it's a base game issue. One that can be exacerbated by mods but a base game issue nonetheless and there's no telling on when or if we'll get another base game patch.

This is probably caused by the game trying to autoresolve a battel with 3 AI factions. The game can’t do this and softlocks. This never happens in vanilla because only 2 AI factions exist at any time.

It may be possible to resolve this by Saving the Game (As a new save do not overwrite any existing saves) loading it in the debug build, switching to one of the offending AI factions and playing the Battle as one of them. Then switch back to your original faction, save and load the save in the normal game build. However this doesn’t always work, sometimes braking the game in even more exciting ways.