SYMPTOMS
When you are connecting to a Team Workspace that contains a Team Folder Application (such as Discussion Forum, Document Library, Team Calendar, Team Contacts, or Team Tasks), any of the following error messages may appear in the Summary view for the program:
Summary view creation failed: Could not open the Public Folder store.
Summary view creation failed: Unknown Error
Summary view creation failed: Could not logon. Make sure your user account has a default mail profile.