Try this:

=IF(AND(COUNTA(A1:A4)0,COUNTA(A1:A4)<4),"Incorrec t entries","")

Change the wording of "Incorrect entries" to whatever message you
would like.

Hope this helps.

Pete

On Jul 21, 2:07 am, "Mary Lancaster" wrote:
Hi,
I hope someone can help me with this. I have four cells A1:A4. If all four
cells contain data or are blank then thats okay. But if 1, 2 or 3 cells
contain data then I want a warning that all cells must be blank or contain
data.

Thanks
Mary