This indicates a split archive . Because BIOS collections can be large, they are often split into smaller parts (001, 002, etc.). You need all parts in the same folder to extract the data successfully. Why the "Verified" Tag is Crucial
: Ensure you have all sequential files (001, 002, etc.) in the same folder before attempting extraction with RetroBat Check fullbiosretrobat700ms 7z001 verified
Inside, you may find a Readme.txt listing required BIOS per system. This indicates a split archive