How to clear Outlook's cache

After you migrate to Exchange Online you MUST empty your Outlook's auto-complete list to ensure that all your emails get addressed using Exchange Online's University-wide address book. If you do not do this, emails addressed using your Outlook's auto-complete list will not get delivered; you will not get a delivery failure notice.

Outlook on PC

1. Open Outlook.
2. From the File menu, select Options.
3. Click the Mail menu item.
4. In the Send messages section, click the Empty Auto-Complete List button.
5. Close the Outlook Options window.

Outlook for Mac

1. In Outlook, select your Exchange Online mailbox folder in the left-hand navigation pane.
2. Right-click (Command-click) to open the menu and select Properties.
   [Alternative method: with your folder highlighted, go to File > Folder > Properties].
3. Click on the Empty Cache (Warning - there is no turning back!).
4. Click OK  to close the window.