I've asked this question on other forums, hoping for some guidance. I have an iMac running 10.11.6 and have updated rsync to 3.1.2 (using homebrew). I am trying to use rsync to back up from my iMac to an attached USB hard drive or thumb drive using this command: rsync -vaE --progress --delete /source/files/ /destination/files/ My goal is to have the destination be an exact copy of the source. My problem: I use Finder to originally copy /source/files/ to /destination/files/. Using Get Info, I see the size and number of items in source and destination are exact matches. Then I run the rsync command above to verify destination is an exact match to source, but it rewrites many files (some hidden, some not) before completing successfully. But if I do another Get Info on source and destination the size and number of items no longer match. A further oddity: if I run rsync twice in a row, the second run still finds files to write/rewrite. Why is this? Shouldn't the first run have exactly synchronized the destination to the source? I should also add that I do the rsync on several large groups of files (music files, images, documents) and sometimes rsync runs quickly and as expected. The odd results described above do not happen every time. I have also tried dropping the -E option (is it still required?) but it doesn't seem to matter. Shouldn't destination be an exact copy of source after rsync, with the same size and number of items, etc? Shouldn't rsync exactly match destination to source, incl resource forks, .DS_store, hidden files, etc.? TIA for any help and insight.