Have you looked at the other formulas to see if they refer to the original one you are trying to remove?

If you are using CR XI R2 (a free upgrade you can download from their website), you can right-click on a formula and choose "Find in Formula" and this tells you everywhere it's used at.

A cool trick that most people don't know about is that if you change the data type that the formula returns and then run the report, you'll get an error message and it shows you what part of the report got broken. It takes you right there.

Formulas can also be hidden in subreport links, SQL parameters and the record selection formula.

I have lots of cool tips and tricks for using and writing formulas in chapters 5-7 of my book Crystal Reports Encyclopedia.

Not sure if R2 is being installed with CR by default yet. But I doubt it. If you check your version, R2 is listed as version 11.5 and not 11.0. Definitely get the free upgrade if you need it. Lots of cool features. Also check out page 7 of Crystal Reports Encyclopedia for the index of how to use all the new features.