I've discovered a bug (or is it a feature? ) in the Contacts App. Try this... Edit an existing contact which contains an address (street address, city, state etc). Blank out all the fields on the address edit screen and try to save your changes. It will not allow you to save. You must have an entry in at least one of the fields. I discovered this when updating an address of a friend who moved and I did not have their new address.