Hello;

Below is a brief description of the problem and the code:

There's a starting value in Each of the UNLOCKED cells C12, C14, C16.

The purpose of the w/s Change event is (3 scenarios for now):
....If the value in cell C12 is changed manually, cell C16 is automatically
calculated
....If the value in cell C14 is changed manually, cell C16 is automatically
calculated
....If the value in cell C16 is changed manually, cell C14 is automatically
calculated

The manually changed values are displayed in dark yellow fill.

====================================
Private Sub Worksheet_Change(ByVal Target As Range)
Const sInputCells = "C12,C14,C16"
' manually input ANY 2 of C12, C14, C16 values and the 3rd is automatically
calculated
' and displayed in light green fill

With Target
If Not Intersect(.Cells, Range(sInputCells)) Is Nothing Then
If .Column = 3 Then
On Error GoTo ErrHandler
Application.EnableEvents = False
If .Row = 12 Then 'calc C16
.Interior.ColorIndex = 6
.Offset(2, 0).Interior.ColorIndex = 6
.Offset(4, 0).Interior.ColorIndex = 35
.Offset(4, 0).Formula = "=E12*C19*60/C9/C14"
ElseIf .Row = 14 Then 'calc C16
.Interior.ColorIndex = 6
.Offset(-2, 0).Interior.ColorIndex = 6
.Offset(2, 0).Interior.ColorIndex = 35
.Offset(2, 0).Formula = "=E12*C19*60/C9/C14"
ElseIf .Row = 16 Then 'calc C14
.Interior.ColorIndex = 6
.Offset(-4, 0).Interior.ColorIndex = 6
.Offset(-2, 0).Interior.ColorIndex = 35
.Offset(-2, 0).Formula = "=E12*C19*60/C9/C16"
End If
End If
End If
End With
ErrHandler:
Application.EnableEvents = True
End Sub
====================================

With unprotected sheet and only the above w/s Change event in effect ( XL
2003 Options: 1,000 Iterations, Max. change 0.00001, though not really
needed!):
1) procedure works fine by manually changing the values in C14 and/or C16
2) procedure works fine by manually changing the value in C12 provided the
preceding manual change(s) was in C14
3) procedure FAILS when manually changing the value in C12 if the preceding
manual change(s) was in C16.

So it seems to me that the problem (circular ref., 0.00 or DIV/0!) is most
certainly with the above Change event code.

I would be glad to attach the simple test w/b (single w/s), if I only know
how !!
Your help in identifying the problem would be greatly appreciated.
Thank you kindly.