I also encountered the issue again yesterday - no laptop hibernation or
anything. In the morning the calendar of the employee showed fine. Later in
the afternoon I could not view it anymore and received the error. This is
still broken.

"hl2" wrote:

Our company also have Exchange 2003 with Outlook 2007 clients (we've
deployed Office 2007 to about 500 clients). A lot of people experience
this error. E.g. clicking a shared calendar will display "The
messaging interface has returned an unknown error."

Also, "View group schedules" have an error. If you add some persons
(e.g. 40-50) and try displaying their calendars, it will not update
all information on all persons. Sometimes all you can see is the free/
busy information, even though you are allowed to read the content of
their schedule.

It seem to me that Outlook 2007 have a bug when it comes to connecting
to Exchange 2003 servers, and I would have no problem showing this
problem as it happens like every day.

The problem is not related to Laptops and/or power save. I have this
problem at several workstations with no power-savings. Also, the
problem is present at both Vista and XP SP2. We have no problems on
our Outlook 2003 clients.