How can I find a lost folder in Outlook?

"Try this:

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

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

Search ""All Mail Items"" for an email that you know is in the folder.
Right click and select ""Find All"" then ""Related Messages""
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 :

Search ""All Mail Items"" for an email that you know is in the folder.
Open the message and press Ctrl-Shift-F to open the Advanced Search dialog
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."

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!

"If you have access to powershell on the exchange server, you can run the following script to dump all folders in the exchange system (courtesy of blogs.msdn.microsoft.com/deva/2012/05/10/exchange-powershell-how-to-get-list-of-mailboxes-folders-subfolders-items-in-folder-foldersize-programmatically/):

Add-PSSnapin Microsoft.Exchange.Management.PowerShell.* -erroraction SilentlyContinue
$saveto = $env:USERPROFILE + ""\\OutlookFolderList.csv""
Get-Mailbox | Select-Object alias | foreach-object {Get-MailboxFolderStatistics -Identity $_.alias | select-object Identity, ItemsInFolder, FolderSize} | Export-csv $saveto -NoTypeInformation

If you want information for a particular user, you can use something like this:

Add-PSSnapin Microsoft.Exchange.Management.PowerShell.* -erroraction SilentlyContinue
$who = $args[0]
$saveto = $env:USERPROFILE + ""\\OutlookFolderListFor$who.csv""
Get-MailboxFolderStatistics -Identity $who | select-object Identity, ItemsInFolder, FolderSize | Export-csv $saveto -NoTypeInformation

These methods create CSV files that can be easily opened in a spreadsheet and searched."