Load the DAT into CLRMamePro, point it to your ROM folder, and run a scan.
In this guide, we will break down why this happens and how to get your FBNeo romsets fixed and running for free. Why Does FBNeo Say "Romset is Unknown"? romset+is+unknown+fbneo+fixed+free
Do not try to repair individual files. If you have hundreds of "unknown" errors, your base set is corrupt. Delete the old files. You need a clean slate. Load the DAT into CLRMamePro, point it to