Dave,

THANK YOU very much. This will work perfectly for this application.

"Dave Peterson" wrote:

How about just using an adjacent cell (B1???) with a formula like:

=if(counta(a1:a4)<2,"","Please--only one entry in A1:A4")

Format as big bold red letters.

QTPRM wrote:

I have created a range of cells (A1:A4) with an in cell drop down-list using
data validation. I want to limit the entry from the list to only one of the
four cells. If A1 has an entry I need to restrict entry in A2:A4. If A2 has
an entry I need to restrict entry in A1,A3, & A4 etc.

Note: I am using SUMIF to total columns 1-4 based on the entry of from the
drop-down list.

--

Dave Peterson