Fixed free ROM sets can be downloaded from reputable sources, such as the FBNeo website or other trusted repositories. When using these ROM sets, ensure that you're downloading them from a trusted source to avoid any potential issues.
you are not alone. This error is a security measure, not a bug; it means the emulator doesn't recognize your ROM file's name or its internal digital signature (CRC). Steam Community romset+is+unknown+fbneo+fixed+free