Romset+is+unknown+fbneo+fixed+free ~upd~ Access
: FBNeo is updated frequently. If your romset is old and your core is new (or vice versa), the naming conventions might have changed. Using a tool like ClrMamePro
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. romset+is+unknown+fbneo+fixed+free