For the best performance in both Outlook and ClearContext operations, Exchange users should check the following settings:
Cached Exchange Mode
Cached Exchange mode is the default mode for current Outlook versions. Please verify in the Outlook Account Settings screen that your accounts are enabled for Cached mode and not online mode, otherwise you may experience very slow performance. Additionally, if there is an option for how much offline mail to store, choose either all mail or a reasonably long time frame such as one year.
Offline Address Book
Make sure that the address book has been downloaded locally to ensure that ClearContext can resolve Exchange addresses quickly and correctly. To download, go to Send/Receive tab/menu and select Download Address Book. The option may be under Send/Receive Groups area.