Change vCard Format from 3.0 to 2.1

• 1). Click the "Go" button at the top of your screen and select "Applications" from the sub-menu. Alternatively, click the "Finder" icon on your screen's dock, click the "Applications" tab in the sidebar,and double-click the "Address Book" icon in the Applications folder.
  
  
• 2). Click "Address Book" on the menu at the top of the screen and select "Preferences" from the drop down list. Select the "vCard" button in the Preferences window and click the circle next to "2.1."
  
  
• 3). Click the red button in the upper-left corner of the vCard window and click the contact you wish to export. Select "File" at the top of the screen and select "Export" and "Export vCard" from the sub-menu to export the specific contact to the 2.1 vCard format.
  
  

Remove Duplicate Contacts

• 1). Click the "Go" button at the top of your screen and select "Applications" from the sub-menu. Alternatively, click the "Finder" icon on your screen's dock, click the "Applications" tab in the sidebar and double-click the "Address Book" icon in the Applications folder.
  
  
• 2). Select "Card" on the menu at the top of the screen and click "Look for Duplicates" in the pull-down menu.
  
  
• 3). Click the "Merge" button to combine duplicate entries into the existing vCards.
  
  

Export and Re-Import Contacts

• 1). Open the Address Book application on your computer and click the first contact at the top of the contact list. Hold down the "Shift" key on your keyboard and scroll down to the bottom of the contact list.
  
  
• 2). Click the last contact and release the "Shift" key. Click "File" at the top of the screen and select "Export" from the drop-down menu. Click "Export vCard" in the sub-menu.
  
  
• 3). Enter a name for the saved vCard group and click the "Save" button. Press the "Delete" button on your keyboard and click "Delete" on the confirmation pop-up box.
  
  
• 4). Press and release "Command" and "Q" simultaneously to exit Address Book, and re-launch Address Book. Click "File" at the top of the screen and select "Import" from the pull-down menu.
  
  
• 5). Locate the saved vCards file and click it once to highlight it. Click the "Open" button to import the contacts back into Address Book.