Factorio Forums

Usually when joining a multiplayer game and you have different mods installed, you get the error 'Active mods configuration doesn't match'. But this check uses the currently enabled mods in the mods list, not the actual loaded mods.
You can lauch factorio without mods enabled, then enable the mods the server needs and connect without restarting factorio. The map will be downloaded, then an instant desync occurs (also showing 'Migrated content' on the client right before desync, if there is migrated content).

Steps to reproduce:

• Put the mods the multiplayer game needs in the mods folder
• Start factorio and disable at least one mod
• Restart factorio
• Enable the mods you disabled in step 2
• Join the multiplayer game --> instant desync

This can happen especially often if you have all the mods you need in the mods folder and often switch between them, as different mp games need different mods.

Thanks for the report, I actually wanted to change it for a long time.

The game will automatically restart once you exit the mod settings while if made any changes.