Remove duplicates

[quant]

I don't have an outlook, so don't know whether it works the same (ie. whether importing from outlook stores some kind of URL), but there is "create logically linked items for duplicate URL" setting, which should make clear that item already exists in UR file if you by mistake import it second time.
And if you have parents pane open (which I do all the time in my main layout to have the whole picture of my data structure), you can immediately see the location of the existing item.