Depends upon what you are trying to delete. You cannot delete default address books: 'Personal Address Book' 'Collected Addresses' If you try to delete them, then a new one will auto appear. If you add email addresses to address book by clicking on the FROM or TO header email address and select 'Add to Address Book', it will auto add to the 'Personal Address Book'. 'All Address Books' is not a true address book, it is like a search folder with the ability to display everything. You cannot delete 'All Address Books'. You can stop outgoing email addresses going to the 'Collected Addresses'. You can switch it off so no outgoing email addresses are collected or choose another address book. Tools > Options > Composition > Addressing tab To Stop all collecting: uncheck : 'Automatically add outgoing email addresses to my' To select another address book for collecting: select: Automatically add outgoing email addresses to my' and select another address book from the drop down list. click on OK Otherwise to delete any address book or Mailing List you have created: Select the address book in the left Directory Pane click on 'Delete' OR right click on address book and select 'Delete'.