Last week, I asked a trick question--kind of. The truth is, to the best of my knowledge, you can't actually change the default Contacts folder. There's a compromise of sorts, but nothing that fully fills this need.
You can move the folder you use the most up in the Navigation Pane hierarchy, but it's mostly for looks. To do so, right-click the folder that you want to be the default folder and choose Move Up In List. Repeat as many times as necessary to position that folder at the top of the list. Some readers report that this does not work for them and unfortunately, I have no explanation to offer. Outlook should remember the order, from session to session. Unfortunately, regardless of list order, Outlook still selects the Contacts folder. That's what I meant when I said this technique was for looks only. I've found no way to force Outlook to select a folder by default other than the out-of-the-box Contacts folder.
The position in the list, without the inherent default behavior doesn't serve much purpose. Most uses change the list order thinking the position will change the default address book--that you can do! Txclimber offered the basic steps for changing this default. Thanks Txclimber. For more details on changing the default address book, read Get Outlook to default to the address book you choose.
Susan Sales Harkins is an IT consultant, specializing in desktop solutions. Previously, she was editor in chief for The Cobb Group, the world's largest publisher of technical journals.