Hi Andy! Thanks for the reply.
I may just delete everything on DRIVE2 overnight, and then try rsync with: time sudo rsync -aHSxvvv --human-readable --delete --numeric-ids -- info=progress2,stats2,name2 -- exclude={"/dev/*","/proc/*","/sys/*","/tmp/*","/run/*","/mnt/*","/media /*","/lost+found"} /media/user/DRIVE1/ /media/user/DRIVE2/ ; date BTW, thanks for the tip about xxsum. I will have to give that a try!