(posted this to the wrong group before, sorry) I have an application (C# .NET 3.5) which needs to access Outlook. I create new folders in the calendar folder and add AppointmentItems to it (from the Office Interop libraries). It works fine, but not if the computer is part of a domain where Outlook is linked to Exchange. When creating a new folder for example (to contain AppointmentItem objects) I simply get an exception "Cannot Create Folder" Does anybody know what needs to be done in order to allow my application to create folders in Outlook? Another problem I'm facing is that with Outlook 2003 it seems the user can only grant my application access for 10 minutes. (Office 2007 does not seem to have this limitation). The idea behind my application is that it runs in the background, synchronizing with another data source continuously. So they get a lot of messages form outlook asking to grant my application access to Outlook. Thank you.