My folder is missing

Only folders containing items of the same item type that is active are displayed. Subfolders (such as a calendar folder under an e-mail folder), will not show in the Mail pane. When you have folders of one item type in the folder of another item type, switch to the Folder List pane.
1. On the Go menu, click Folder List.

The folder may have been deleted from Favorite Folders in the Mail pane. Deleting a folder here deletes the corresponding folder in the Folder List.