Why Does Conditional Formatting Freeze Excel?

[Dazzawm]

I have used conditional formatting to highlight duplicate values on a sheet. It only consists of 600 rows by 7 columns but whenever I try to scroll etc excel freezes for quite a time. Why is this, how can it be avoided please? Thanks.

 

[jkpieterse]

There must be something else at play, if I create a sheet with just 600x7 cells with a CF for duplicates it scrolls just fine. A bit slower than without, but that is to be expected.

 

[skorpionkz]

upload the Excel file you have, so we can see what is going on

 

[Dazzawm]

I copied all the data to a fresh sheet and it does not appear to be as bad. Thanks.