If you have tried solutions 1 through 6 and the error persists, the issue is likely physical hardware degradation.
If the sound bank relies on a specific version of DirectX (June 2010), modern Windows may be missing a legacy DLL. Black Ops 2 Sound Bank Failed To Load Cmn-root.polish
Try these solutions in order. The first solution resolves over 80% of cases. If you have tried solutions 1 through 6
Black Ops 2 was designed for Windows 7/8 and does not handle modern UAC restrictions well. If you don’t need Polish audio:
Best for: Corrupted or missing files due to updates or drive errors.
If you don’t need Polish audio: