Just to avoid any side effects I but the code in a separate executable
and disable any COMAddIns for outlook.

The code just retrieve the calender-folder of an User an terminate.
The method DisposeObject.Singe use Marshal.ReleaseComObject(o) and set
the reference to null. As I can see so far, everythink in the code
should be allright.

Calling the GetSharedFolder() with User "User1" works fine, calling
the function with "User2" cause outlook to stay in memory.

I have still no idea, what's wrong.

Markus

=====================================================
private static void GetSharedFolder(string cUser)
{
Debug.WriteLine("GetSharedFolder");
try
{
 Outlook.ApplicationClass oOutlook = new ApplicationClass();
 Outlook.NameSpace oNS = oOutlook.GetNamespace("MAPI");
 Recipient oRep=null;
 MAPIFolder oFolder=null;
 oRep =  oNS.CreateRecipient(cUser);
 if (oRep != null && oRep.Resolve())
 {
   oFolder = oNS.GetSharedDefaultFolder(oRep,

      OlDefaultFolders.olFolderCalendar);
   Debug.WriteLine(oRep.Name + " " + oFolder.Name);
 }
 DisposeObject.Single(oFolder);
 DisposeObject.Single(oRep);
 DisposeObject.Single(oNS);
 DisposeObject.Single(oOutlook);
}
catch (SystemException e)
{
 Debug.WriteLine(e.Message);
}
GC.Collect();
GC.WaitForPendingFinalizers();

}

public class DisposeObject
{
 public static void Single(object o)
 {
    if (o != null)
    {
    int iRefCount = Marshal.ReleaseComObject(o);
    o = null;
     }
 }
}