Iteration frustration

[sharkfoot]

I have a workbook that has an issue with a circular reference. I figured out to goto OPTIONS, CALCULATIONS, then select the ITERATION checkbox and that fixes the problem, but I save and close the workbook and the problems returns. The ITERATION checkbox is no longer checked and excel tell me there is a problem with a circular reference again.

How do I get the iteration checkbox to remain checked when the workbook is reopened? I tried this:

Private Sub Workbook_Open() 
    Application.Iteration = True 
End Sub

But the problem remains. Ideas?