From Tim: "I've scoured your various sites but can find nothing about finding and deleting empty folders in Outlook. Do you know of a way or a tool that can do it?"
I'm not aware of any way to make this process easy – you can view the folder sizes in the mailbox properties, but you can't delete folders from this list. You'll have to find and delete them yourself.
To view the size of all folders: Right click on the folder at the top of your mailbox which is also the 'Outlook Today' folder, and choose properties, then folder size button.
To view the size of a specific folder and it's subfolders: right click on the folder and choose properties, then folder size.
This is one reason why I recommend using categories, views, and search folders instead of multiple folders to sort your email. Another reason is that it's easy to lose mail when you have hundreds of nested subfolders.
Published March 7, 2006. Last updated on June 17, 2011.