Why does UPDATEALL ask for confirmation?

I have a very simple button for making backups from a particular partition:

Copy "P:*" to "D:\backup\p" FILTER=SysFiles_ignore UPDATEALL

So I'd expect it to do what the help says the UPDATEALL does, namely copies the files that do not exist or are different into the D:\backup. Which works, but, I'm a bit annoyed that after DO finishes counting the files in the "P:", it pops up a requester about a file already existing in "D: ... "and whether I want to overwrite it.

So why does this dialogue window pop up, or, in other words, how do I get rid of it? I mean, if I just told DO to copy the changed and added files, why ask me again unless I'm doing something wrong.

Try adding the following to your command.

WHENEXISTS=replace

That makes te dialogue not pop up, which is nice - thanks!

Still, I don't understand why was it there in the first place, must be something obvious that I'm missing.

People may still want to know and confirm (or skip some of) the files that get overwritten while automatically skipping the ones that haven't changed.