I originally considered posting this at apple.com's Unix forum, but with 1 post a week it's a rather sad (and unproductive) place... was hoping for your expertise: I'm trying to use rsync to run a checksum comparison between two folders. Consider this behavior: rsync -nrcvv --itemize-changes /Volumes/2748A/3_Elements/d_Video/c_Camera\ Originals/062315-301/BPAV/CLPR/EPSN0222_01 /Volumes/Untitled/BPAV/CLPR/EPSN0222_01 building file list ... done delta-transmission disabled for local transfer or --whole-file cd+++++++ EPSN0222_01/ >f+++++++ EPSN0222_01/EPSN0222_01.MP4 >f+++++++ EPSN0222_01/EPSN0222_01.MP4 48000.pek >f+++++++ EPSN0222_01/EPSN0222_01.SMI >f+++++++ EPSN0222_01/EPSN0222_01I01.PPN >f+++++++ EPSN0222_01/EPSN0222_01M01.XML >f+++++++ EPSN0222_01/EPSN0222_01R01.BIM total: matches=0 hash_hits=0 false_alarms=0 data=0 sent 308 bytes received 62 bytes 740.00 bytes/sec total size is 52949308 speedup is 143106.24 About half a dozen things here don't make sense to me: What does the data sent/received signify in the -n mode? The data that would have been transfered, or the actual transfer? The file EPSN0222_01.MP4 48000.pek does not exist in the DEST folder. Why are its itemized changes identical to the other files? All the other files are identical (tested with md5 command). Why are they listed? Why 0 matches? Why 0 data? Thanks!