Over the years, my contacts list has become kind of crufty. Which is no surprise, really, as I’ve essentially used the same list since I owned a Palm Tungsten C back in 2003. I keep backing it up, moving it to newer, better devices and systems, but over time, there are serious issues in that database.
Like duplicated contacts, for example, each with a different subset of addresses, phone numbers, and email addresses. It’s a pain to go through them, one by one, and copy over information from each duplicate contact to a final, master contact for each person in my list. The OS X Contacts app, though, has a couple of helpful features to make this a bit easier.
First of all, when you have your Contacts app launched, head up to the Card menu and choose “Look for Duplicates.” The Contacts app will search through all of your Contacts and find the ones that have the same name. It will then offer you a chance to Merge them. If you want to do that, click on the Merge button in the bottom right, and OS X will put all the duplicate contacts together so that you have only one name per contact, and no more duplicates.
The Contacts app will not tell you which of the contact entries are duplicates, though, so you may want to go the manual route. In addition, it won’t find contacts that are the same, but have differently spelled names in them due to typos. In that case, you’ll have to scroll through your contacts to find two or more you want to merge. Command-Click on each of the contacts you want to merge, then go back up the the Card menu and choose “Merge Selected Cards,” or hit the Command-Shift-I keys on your keyboard after you’ve selected multiple contacts.
Via: Macworld Hints