If you have a clone like mslugx.zip (Metal Slug X) but error appears:

FBNeo is actively developed, and its ROM requirements occasionally change to match better, more accurate game dumps. If your ROMset is old (from an older version of FinalBurn Alpha) and your emulator is new, they may no longer match.

| Cause | Description | |-------|-------------| | | Your ROM was dumped for MAME 0.xx, but FBNeo uses its own independent datfile (updated every ~month). | | Incorrect naming | Zip file name doesn't match the driver name (e.g., streetfighter2.zip vs expected sf2.zip ). | | Missing parent ROM | You have a clone (e.g., sf2ce.zip ) but not the parent set sf2.zip required to supply shared files. | | Non-merged vs split set mismatch | FBNeo expects split or non-merged sets; merged sets often cause errors. | | Corrupted or modified ROM | Even one byte changed alters the checksum. | | Wrong emulator version | Very old FBNeo version may predate a newly added ROM. |

fbneo -listinfo > fbneo_games.txt

The "Romset is unknown" error is a version mismatch. To fix it, ensure your and your ROM Set are from the same time period. For the best experience, always use a ROM set specifically curated for FinalBurn Neo.