Microsoft Excel - Conditional formatting, finding duplicates I need to highlight duplicates in column A, but only if column B is equal to 10.

67890    10

67891    10

67891   20

67891   30

67892   10

67892   20

67894   10

67895   10

67891   

In this example, what I want it to do is, as soon as I input the value on column A the cell automatically changes colour.

I have tried using sumproduct and countifs on conditional formatting, but it does not highlight the values.

Thank you in advance.
I found a solution; it's not "pretty", but it works. Unfortunately, it is a bit hard to describe, so I'll make an
example file with explanations available, instead. In short, it uses


a "helper cell" the locate and mark duplicates
Excel's use a formula to determine which cells to format Conditional Formatting option to then color the original cells