Try this:

I don't know if this will work on a shared file but it works on non-shared
files.

Create this named formula:

Name: IsFormula
Refers to:

=GET.CELL(48,INDIRECT("RC",FALSE))

Set the validation:
Select the cells you want to validate.
Allow: Custom
Formula: =IsFormula
Uncheck: Ignore blank

I can't figure out why, but it doesn't work unless Ignore blank is
unchecked.

Biff

"Bob" wrote in message
...
A member of this forum provided the following UDF to display a formula
within
a cell:

Function GetFormula(Cell As Range) As String
GetFormula = Cell.Formula
End Function

I tried creating the following "custom" Validation rule for cell A1 (which
happens to contain a formula):

=LEFT(GetFormula(A1),1)="="

but it is not working correctly (I get a "Named range cannot be found"
error
message).

I want to ensure that someone doesn't inadvertently over-write a cell
containing a formula.

Can anyone show me how to do this using a Validation rule? I am aware of
a
solution using Conditional Formatting, but I really need to use a
Validation
rule.

Any help would be greatly appreciated.

Thanks,
Bob