Your problem is that " " is not blank. I know it looks blank to you, but not
to Excel. You need to use null ("") to have ISBLANK be true. So change your
formula to :
=IF(OR(TODAY()<Due_Date,J9="COMPLETED"),"",TODAY()-Due_Date)

Your conational formula would be:
=and(not(isblank(a1)),a11)

which can be simplified to:
=and(a1<"",a11)

which can be simplified to:
=a11

In the future, you can avoid these annoying problems by always using null
("") rather than space (" ") to signify an empty cell.

Regards,
Fred


"Pat" wrote in message
...
I have read & tried several CF solutions, but they are not working for me.
I am working with Today() date, Due_Date, & days_late.

I have a formula in the days_late column
). This formula
gives me days_late or leaves that column blank (" ").

I want 5 cells to turn red if days_late1. All my attempts at CF have
also
turned the blank (" ") cells red also. I have tried ISBLANK and
NOT(ISBLANK).
--
pls