Quote Originally Posted by Ellis Dee View Post
You absolutely do have to modify the archive bit, obviously. You have to unset it on files you back up. That's the whole point of what you're recommending. (RoboCopy failed in my first test because it didn't have privileges to unset the archive bit on files in ProgramData. Which is weird, but whatever. Running as administrator solved that.)
Modify archive bit to backup? No no and once more no...

File which has no archive bit set, is already backed up - in other words file is not modified since last backup. So - when doing incremental backups there is absolutely no need, to modify file attributes.

aand... neither when doing full backup as one could use '/MIR' switch.