> Is this the most efficient method?

Usually the rebuilder as an "adder" is faster (esp. with recompress option disabled).
I usually update this way: Do a full scan with all fixoptions enabled (well...I don't have any addpaths, so fixmissing only does some quick fixes).
After that I add the new sets with the rebuilder (with recompress off). For that procedure I don't leave the scanner. I simply drag&drop the new files/folders in the scanresults window. This will use the current rebuilder options (i.e. rebuilder destination points to the rompath(s)) and adds the files to the collection. After that drag&drop an automatic fastscan is performed.


> It seems to take a long time to fix a rom that is fairly
> large.

Depends on the fixoperation. Name/case changes are done without recompressing the zip. Add/Remove Operations require some zip/unzip (for backup) operations which may take some time. You may increase the speed by enabling the zipcache in settings->zipsettings.
Really slow operations are: checksum->sha/md5/integrity checks, advanced->fix missing scans all sets and using the full zip structure scan in settings->zipsettings. Usually you don't need these options.

Roman Scherzer
ClrMamePro