Thanks Dave and all, I do have the analysis tool pack loaded on my source
spread sheet.
Can you give me an example of how i would include the hidded colunm in my
formula.

thanks

"Dave Peterson" wrote:

=networkdays() is part of the analysis toolpak (in xl2003 and below).

Since not everyone may have that addin loaded, I'm guessing that excel wants to
make sure conditional formatting doesn't break.

(I sometimes use an adjacent cell (and hide the column). And put the formula
there. Then use that cell in the CF rule.



Suddes wrote:

When using conditional formating i get the following message when trying to
use NETWORKDAYS' function

"you may not use references to other worksheets or workbooks for conditional
formatting criteria"
! any ideas why this would be the case

many thanks

--

Dave Peterson