The phrase "FBNeo Romset Unknown" usually pops up when someone is trying to get their retro gaming setup running, only to find that their FinalBurn Neo emulator doesn't recognize their files.
If any of these do not match the librarian’s master list—even by a single byte—you get the "romset unknown" error. fbneo romset unknown
Open your FBNeo menu or check the "About" section to see the version number (e.g., v1.0.0.03). Find the Matching Set: The phrase "FBNeo Romset Unknown" usually pops up