Cocktail is a general purpose utility for OS X that lets you clean, repair and optimize your Mac. It is a powerful digital toolset that helps hundreds of thousands of Mac users around the world get the most out of their computers every day.

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Clean up your contacts

If you open Contacts and find multiple entries for the same contact, it's time to put things in order.

To do this, choose Look For Duplicates from the Card menu. Contacts will do exactly that and, after looking, produce a sheet that tells you how many duplicate cards and entries it's found. By clicking the Merge button in that sheet, you can merge those duplicate cards and entries. Optionally you can also merge cards that have the same name but different information.