Hi!

When you say: "I installed the add-in on his computer"

Does that mean it was also loaded? Goto ToolsAdd-Ins

Is Analysis ToolPak checked?

An alternative to using Eomonth and does not need the ATP:

Date in A1 = 1/1/2005

=DATE(YEAR(A1),MONTH(A1)+1,0)

Biff

"Ray" wrote in message
...
I have used the EOMONTH function successfully. But I transferred my
workbook
to someone who did not have the needed add-in installed so it generated a
#NAME? error. So I installed the add-in on his computer but it did not
resolve the #NAME? error. I took his workbook and put it back on my
computer
and it still generates the #NAME? error. But if I open my original file
the
EOMONTH works. I can flip between the two open workbooks and see the
error
on his file, but not on mine. Tried F9 to force a recompute, no help? Any
ideas?