Are you saving the file in XLS format?

You need to first save in XSLX or XLSM format ...

"Harold" wrote:

I have a IF Function formula nested 8 levels deep. I'm trying to add 15
levels, but I keep getting an error saying that the formula "uses more levels
of nesting than are allowed in the current file format". I'm using Excel
2007; the file format is xlt for file compatibility, but even if I save it as
xltm I get the same message. Help says 2007 can nest up to 64 levels!