Hello Bob,
Unable to make this one work as well

"Bob Phillips" wrote:

You could use data validation with a custom formula of say

=COUNTA($M$4:$M$10)<2

which will trap entry on input.

--
HTH

Bob Phillips

(remove nothere from email address if mailing direct)

"Serge" wrote in message
...
I need a solution for entering data in any one cell out of seven in a
range
in one row. I need to be able to select any cell but only one, if data
is
entered in an other cell in the same range, it needs to create an error
message