XL97: #VALUE! Appears When Function Is RecalculatedID: Q175290 
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In Microsoft Excel 97, cells that contain formulas that refer to user-
defined functions may return a #VALUE! error after you run a Visual Basic
for Applications macro or perform any action that causes the worksheet that
contains the formulas to be recalculated.
Also, if a Visual Basic subroutine is running when the formulas are
recalculated, the subroutine may stop without warning.
These problems may occur if an error occurs in a user-defined function
while Excel is recalculating the worksheet.
For an example of this problem, see the "More Information" section later
in this article.
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http://www.microsoft.com/support/supportnet/overview/overview.aspTo work around this problem, press CTRL+ALT+F9 to force the values to be recalculated. When you do this, any formulas that refer to user-defined functions are recalculated correctly.
   Function MyFunction(CellRange As Object) As String
       On Error GoTo ErrorHandler                       'new line
       If CellRange.Interior.Pattern = xlNone Then
           MyFunction = "yes"
       Else
           MyFunction = "no"
       End If
       Exit Function                                    'new line
   ErrorHandler:                                        'new line
       '  You may want to use the following statement 
       '  to output the type of error result instead
       '  of a string result.
       'MyFunction = CVErr(xlErrValue) 
       MyFunction = "error"                             'new line
   End Function 
In this user-defined function, the line "On Error GoTo ErrorHandler" causes
the function to continue if an error occurs. In this case, the error-
handling code causes the function to return a value of "error," instead of
"yes" or "no." After the formulas return "error," press CTRL+ALT+F9 to
recalculate the worksheet.
Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.
In Microsoft Excel 97, if a user-defined function returns an error value,
the formula that called the user-defined function and any other formulas
that call the same user-defined function may fail to be recalculated
properly. When this happens, the formulas may return a #VALUE! error.
Also, if the user-defined function returns an error value, any running
Visual Basic subroutine that caused the recalculation to occur may stop.
This may cause problems if the subroutine is running unattended.
To see examples of these problems, follow these steps:
      Function MyFunction(CellRange As Object) As String
          'This line will fail when you delete a row from the worksheet.
          If CellRange.Interior.Pattern = xlNone Then
              MyFunction = "yes"
          Else
              MyFunction = "no"
          End If
      End Function
      Sub TestDelete()
          Rows(2).Delete              'Deleting a row forces
                                      'recalculation.
          MsgBox "Delete succeeded."
      End Sub 
=MyFunction(C10) 
   and press CTRL+ENTER.
Additional query words: XL97
Keywords          : xlvbainfo xlformula 
Version           : WINDOWS:
Platform          : WINDOWS 
Issue type        : kbbug 
Last Reviewed: July 12, 1999