I will try that, thanks. This is Windows 10, so some strange things happen to older games and running as admin sometimes helps... The mod is exactly in the place it needs to be (D:\PROG\Firaxis Games\Sid Meier's Civilization 4\Beyond the Sword\Mods\Caveman2Cosmos). I don't think it would help (this is a fresh reinstall of C2C) but it may be the last resort, so thanks a lot. S.