How do I delete a custom messages folder?
You can delete custom messages folders that you no longer require or that you've created accidentally.
Note that Received, Sent, Deleted, Draft, and Scheduled folders, which are provided by default, cannot be deleted.
Go to Messages.
Select the Messages tool from the Tool Menu in your site.
Click the Folder Settings option.
Click the Folder Settings option associated with the custom folder that you wish to delete. Note that Folder Settings is not available for default folders.