> download all of the new/changed ROM(set)s into a directory called "add ROMs".

ok


> I then use Rebuilder to "Merge" these into my existing ROMsets, and if I disable
> the "Remove Rebuilt Sourcefiles" option, my originals remain intact.

The originals in the source. Which should point to that "add roms" folder. The destination should point to your existing old collection.


> Next, I move to Scanner mode, and if I check "Fix Unneeded", any file surplus to
> requirements will be moved to the directory specified in Settings, "Make Backups
> To Folder".


Eh?????


There are 2 ways to add new files to your existing clean collection. One is the rebuilder and the other is scanner's fixmissing.

The rebuilder is usually faster. As said before it has to be configured the following way: Source: points to new collected, not verified, not cleaned roms. Destination has to point to the old verified collection.

Scanner's fixmissing searches defined Addpaths for missing files. It uses a different method to detect the files.


The rebuilder is fully hashbased and should be prefered.

Roman Scherzer
ClrMamePro