Hi all,
thanks for the quick replies.

* I was certain that with Countif(s) and Sumif(s) you MUST use ctrl+shift+enter. I'm surprised that's not the case. So, when do I and when don't I ?

* Anyway, I got the exact same results with just Enter.

* The data I'm working on is list of company names, so it's almost exclusively textual.
It's also the reason why I can post my data, unfortunately


Generally speaking, here is the formula:

=COUNTIF('sheet with original data'!$B$2:$B$28124,'sheet after removing duplicates'!B2)

the company names appear in the 2nd column on both.

Thanks again all!