We have an application that is polling an Excel sheet on
a timer using COM.

On overnight runs we often see OLE Exception with error
code = 0x800ac472.

These often coincide with clicking into Excel from a
screen saver or Windows XP switch to user screens.

If we trap the error and continue things seem OK, but I
was wondering if there is anything we can do to avoid the
exception.

We are running on Excel 2002 under Windows XP SP1

Les