demo.xlsx
The problem I have with highlight cell rules, it only shows duplicates in column E. It seems to ignore comparing them against my other list.

And with the formula =COUNTIF($N$4:$N$600,E2)>0 , I place this in say K2 (which is an empty column) and then I drag it all the way down to K1500. Every single value displayed in K is false though.

I have attached an example to demonstrate.

Thanks