To import an address book, try these steps: From TB, click on 'Address Book' (or 3-bar menu -> Tools -> Address Book). In the list of address books in the left pane, click on the one you want to import (or use 'Personal Address Book'). From the menu bar, select Tools -> Import. An new window 'Import' will open. Click on 'Address Books' and 'Next'. Highlight 'Text file', select 'Next'. Near the lower right corner select LDIF. Navigate to the folder where your LDIF file is located. Left click on it once. Click on 'Open'. Note: when you first look at the imported address book, it may be empty. Click on another one (such as 'Personal Address Book') and then go back to the imported one (or press F5).