Every now and again we see a complaint that Outlook is creating duplicate folders in the folder list, is creating folders with <0w> in the name, or folders named "the file so that changes to the file will be reflected in your item".
Seriously, that is the folder name.
Additionally, you may not be able to delete the folders.
This problem comes and goes with Outlook 2010 and with the release of Outlook 2010 SP2, it's back. It's not a bug in Outlook though, it's caused by an add-in. Typically, the culprit is Norton Anti-spam, but can another non-Microsoft add-in.
The fix: Disable the add-in and restart Outlook then delete the folders.
If you need a quick way to delete folder, drag them to the Deleted Items folder and empty it or drag them to one of the folders that needs deleted then delete the folder. Either method avoids the annoying and repetitive "do you really want to delete this folder?" dialog. Tip 881: How to bulk move Outlook folders
If the duplicate folders are in a shared Exchange mailbox and the folders are being created when one of the people it is shared with opens the mailbox, remove Create Folder permission from the mailbox folders.
Published August 2, 2013. Last updated on June 7, 2017.