Glad I could help. thanks for the response

"Kenya" wrote:

Thank you Kassie,It worked!

"Kassie" wrote:

Try =COUNTIF(A:A,A1)=1, previously posted by Vishu


"Kenya" wrote:

I am working on a spreasheet in excel I have got invoice numbers but i need
to create a warning for repeated invoice numbers.Any help would be most
appreciated.
Thanks