How do you enter a blank? I assume you means a space? If that's the case use

=AND(A1=0,ISNUMBER(A1))


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Regards,

Peo Sjoblom



"el zorro" wrote in message
...
I have a cell A1 which needs to be populated with a number of 0 or greater
and it cannot be left blank.

I used DATA validation with the "Custom" option and populated the
"Formula"
with =A1=0.

I also unclicked the Ignore Blank.

Somehow the validation works for zero or greater but I can still enter
"blank".

Where have I gone in err?

Thanks.