ISEVEN and ISODD are Analysis toolpak add-in functions.

You can achieve the same thing with

CF1: =MOD(ROW(),2) = 0

or

CF1: =MOD(ROW(),2) = 1

In article ,
"Scott Paine" <Scott wrote:

Attempting to use the ISEVEN() or ISODD() functions in Excel 2003 SP2 for
Windows or Excel 2004 for Mac OS X within a Conditional Formatting formula
produces the error:

"You may not use references to other worksheets or workbooks for Conditional
Formatting criteria."

Even though the formula works fine in a cell, the Conditional Formatting
glitch happens even with a new Excel file using a generic test formula such
as: =iseven(2)

These functions would be useful in Conditional Formatting to produce
alternating row formats (shading) for entire columns efficiently instead of
applying a defined style, which for entire columns will tend to greatly
degrade file performance.