\Magicka\Magicka.exe \Magicka\magicka.dll If a mod breaks co-op, restoring these two files reverts you to pure v1.4.16.0 without re-downloading. : v1.4.16.0 is the most reliable Magicka version for actual gameplay. Treat newer betas as experimental. Stick to this build, apply the fixes above, and you’ll enjoy friendly-fire chaos exactly as Arrowhead intended.