Before you can access another person's mailbox data, they will have to grant permissions to you.
1. On the File menu, point to Open, and then click Other User's Folder.
2. In the Name box, type the name of the person who owns the folder or select Name for a list of users.
3. Click the folder that you want to open, and then click OK.
Note: If you use the "Open Other User's Folder" method as outlined, only the primary Outlook folders (Contacts, Inbox, Journal, Notes, Tasks) may be accessed; subfolders are not available. In order to access other than Primary Outlook Folders, the sharer must share their entire mailbox.