Mame 1645 -
This is the hardest part. You need the . Do not mix ROMs from 0.200 with 0.1645. The CRC32 checksums will fail validation. Tools like ClrMAMEPro or ROMVault are essential to audit your collection against the 0.1645 DAT file.
Check CHD version:
rompath roms hashpath hash samplepath samples mame 1645
Record an input (INP) file:
Ensure your chd folder is in the same root as the ROMs. Games like Killer Instinct 2 require the CHD named exactly kinst2.chd inside a folder named kinst2 within the roms directory. This is the hardest part