I have received an EXCEL file and, whenever I open it, it changes the
calculation mode into iterate, even though it has no need for such.
Regardless of whether there is a need or not, I am having trouble
locating the source of this action, which I'd like to defeat. There
seem to be no "do this upon opening" macros listed anywhere, in fact
no macros at all. The This workbook tab is empty and there is only
one oter item listed: Sheet1(summary). Can someone list the places
such a macro could be hiding? Or any other way this could be
happening?

Here's some clues, maybe: On Sheet1(summary) in VBE, I notice that
"enable calcualtion" is set to True. If I change it to false, resave
the file, and reopen, the problem goes away, although I notice that
the enable calculation is back to True again (maybe it's a toggle).
Though that does seem to fix the file, I'd still like to know how it
got set to iterate to start!

This does not happen with my other files.

Thanks much for any help
Dean