I’m also going to link my solution here in case someone finds this thread 
It doesn’t highlight duplicates with conditional formatting or any other live recalculation but does so in manually run passes. And provides some gorgeous UI for resolving those duplicates:
Thank you a lot for this solution, which is indeed much faster on my doc!
Can there be an updated post regarding this? I am using the formula and it works, but for my case I need to filter TWO columns not one.
Eg I have ‘first name’ and ‘last name’ columns, I want to filter out duplicates of people’s registration. I cannot do only one column as many people share the same firstname/last name and they should NOT be considered a duplicate but with this formula does. Any quick solutions for this with the formula without creating a separate column?
Hello @Fawziyah_Nabeelah ,
That is actually not that complicated anymore. You don’t need a helper column (although you can), but you do need one helper field, usually hidden on a settings page. For clarity I put it on my sample page. The switch is optional, but I like it to find duplicate in long lists.
Copy my demo doc and explore the formulas:
Can you please make this doc public? or allow me access? I’m unable to view it!
and thankyou!!
Yes, just changed the settings. In order to see the formulas you need to make your own copy after opening this doc.