Helo Ken,

Excel attends to UpdateNotify with a very high priority, In fact, the
highest! The only provision for not making the RefreshData() call is that
Excel is in the middle of a recalc, or has not received the UpdateNotify()
call.

You write that "in certain circumstances Excel will never call
RefreshData() . . ."

Have you been able to identify those circumstances?

I hope you built your RTD server using the content of the following
article.

285339 HOWTO: Create a RealTimeData Server for Excel
http://support.microsoft.com/?id=285339

Give some thought to the Throttle and Heartbeat.

Try to get some log about what's happening so that you can identify when
and why Excel or your server are communicating. It might be a good thing
to add to your RTD server a log of the calls (just before and just after)
by the server to UpdateData() and include in those the count of ranges
included in the Topics safearray.

Please try to give more information on what's actually happening so we can
see if there's some reason for the symptoms you're experiencing.

Chris Jensen (Microsoft Corporation)