Users are reporting that Outlook is creating folders named "Appt Aux Flags" in their Archive folder. Deleting them doesn't help much as they just keep coming back.
These folders are created by the Norton AntiSpam Outlook addin. Disable the addin and the problem goes away. (We don't recommend using antispam addins anyway as they tend to cause more problems than they solve.)
Once you've stopped the creation of these folders, deleting them can be a hassle because you'll get an "Are You Sure" pop-up if you try to delete the folders one at a time. You can avoid the dialog one of two ways: Switch to the folder list then either drag the folders to the deleted item folder or drag the folders into one folder then delete that folder. At most, you'll get the "Are you sure" prompt only once – when you delete the folder that holds all the other folders.
If you prefer to use a utility or have a lot of folders to delete, try Folder Master for Outlook
Published May 31, 2011. Last updated on April 16, 2012.