I've been asked to modify an XL file that has a user-defined function
named MROUND. This custom function performs the exact same calculation
as the built-in XL formula (Analysis toolpack) that goes by the same
name. Somehow, this custom function seems to be pre-empting the
built-in one, such that if I disable the custom function XL does
revert to using the built-in one and returns the #NAME? error when I
use MROUND in a formula. Any ideas on how I can "un-register" this
custom function???? I've tried disabling it & renaming it, but excel
still will not use the built-in version.

The catch is that I need to use MROUND b/c I have several currency
tables in this file, but I can't use the custom function version b/c
it is somehow interfering with an event macro I have setup. I have
already tried blocking it with the application.enableevents=false &
application.calculation=xlmanual code lines but they don't seem to
block the execution of this custom function when the event macro is
triggered.

Any ideas on how to solve this would be greatly appreciated!!