2016, 2013, and 2010
When using an IMAP email account, an IMAP folder list can be downloaded that displays all the folders contained in your account on the mail server. You can then select which folders that you want to subscribe to or view on your computer.
In Mail, in the Navigation Pane, right-click the top folder for your IMAP account.
Click IMAP Folders.
Click Query.
Click a folder, and then click Subscribe or Unsubscribe.
Note: To select multiple folders, press and hold CTRL as you click folder names.
If you have created a new folder on the mail server in another application or using a web browser, and the new folder doesn™t appear in the IMAP Folders dialog box, you can update the folder list by doing the following:
In Mail, in the Navigation Pane, right-click the top folder for your IMAP account.
Click Update Folder List.
Repeat the steps in the first section and all of your IMAP account folders appear. You can then click Subscribe or Unsubscribe.
2007
Display all IMAP folders that you can subscribe to
In Mail, in the Navigation Pane, click a folder under your IMAP account.
On the Tools menu, click IMAP Folders. Click Query. Display all available IMAP folders in the Microsoft Outlook Navigation Pane In Mail, in the Navigation Pane, click a folder under your IMAP account. On the Tools menu, point to Send/Receive, and then click Update Folder List.
Note: In the IMAP Folders dialog box (Tools menu, IMAP Folders command), if the When displaying hierarchy in Outlook, show only subscribed folders check box is selected when you are downloading folders, only the folders that you subscribe to will be displayed.