How can I find a lost folder in Outlook?

Try this:

1. Find the folder name by searching for the mail item and looking at its properties
2. Select the Go menu, choose Folders at the bottom
3. In the window that appears, find the folder in the drop-down box
4. Press Ok and Outlook should open to that folder

The above did not work for Outlook 2007. The following should:

1. Search "All Mail Items" for an email that you know is in the folder.
2. Right click and select "Find All" then "Related Messages"
3. On the box that pops up, one of the search options is "In:" with a Browse button. Press that button and it will show you which folder the mail item is in and where it is in the folder tree.

Again in Outlook 2013 this has changed :

1. Search "All Mail Items" for an email that you know is in the folder.
2. Open the message and press Ctrl-Shift-F to open the Advanced Search dialog
3. On the box that pops up, one of the search options is "In:" with a Browse button. Press that button and it will show you which folder the mail item is in and where it is in the folder tree.

I have had success with this method:

1. Search for message (or other document). Use the normal quick search, searching for "all files and folders"
2. Open the message/document (double-click)
3. With the message open in i separate Window: Hit Ctrl+Shift+F to open Advanced Search.
4. Advanced Search will open with the folder of the open message selected.
5. Click Browse (top right) to see where that folder is.

This was in Outlook 2010.

If you're in Office 2007 Outlook, this should work. Go to Tools. Click on Mailbox Cleanup. Then click on View Mailbox Size. You'll get a list of all your folders, and if you work down it, you should find the missing one - maybe somewhere quite unexpected!