> SO i have to manually rename area51.chd to area51a.chd and download the new
> area51.chd ?

Looks like you haven't converted it to the new format yet. Do that first, then cmpro should automatically see that it has a wrong name. There's a 7 MB diff-file out there to patch the old to the new chd btw...


> And i still get tons of missing roms and crc errors, even though ive downloaded
> all the roms several times, always picking the largest one...

Looks like you've downloaded wrong ones then ;) If you get random checksum errors, you better check your hardware. Random crc32 errors are usually caused by bad ide cables, bad ram, bad ram timing (overclocked system), etc.
If they don't appear randomly (so they are listed bad in one scan but good in another or vice versa), you don't have to care, then you only got the wrong roms.

Roman Scherzer
ClrMamePro