Which isn't a huge deal for me so using /COPY:DAT worked great.

I was able to test more and the U flag on /COPY was the culprit here. Robocopy Hell - Copy data without NTFS permissions My friend you helped me big time.Migrating file servers - Robocopy syntax question Yes, /mir also deletes files and directories that have been deleted from the source.Oblivion mod managers edit load order by modifying dates on the files, and I'm not sure if dragging-and-dropping would keep that info. Game data to new PC This would probably work well.Is copying the best way to transfer large amounts of files? If you're copying a ton of files that vary in size, using a command prompt robocopy with the multi-thread parameter can make it so you are copying multiple files simultaneously and max out the bandwidth of whatever connection you're using (usb, SATA, ethernet, etc).

Don't know about your merge needs, so take a look into it and do some tests before actually running it.

Is ultracopier still the very best in terms of open source alternative file copying/merging tool ? I used robocopy on a slow network to transfer many gigabyte of data properly configured with retries and everything worked great.

Teracopy vs robocopy vs fastcopy