All Apple computers running the Mac OS X operating system come with a program called Address Book that lets users manage contact information such as addresses, phone numbers and birth dates. The Address Book application stores its data in the .ABBU format, which cannot be opened by other programs. To convert an .ABBU file from Address Book to a comma-separated value (.CSV) file, you must use the Numbers program as a conversion tool.
Launch the Address Book application on your Mac.
Go to the "File" menu at the top of the screen and select the "Import" command.
Highlight the .ABBU file you want to convert and click "Open" to add it to your Address Book data.
Launch the Numbers application and open a blank spreadsheet file.
Go back to Address Book, hold down the "Shift" key on your keyboard and click on each of the records from the .ABBU file.
Drag and drop the Address Book records into the upper-left corner of the blank Numbers spreadsheet document.
Open the "File" menu and choose "Export."
Go to the "CSV" tab at the top of the pop-up window, set the text encoding to "Unicode (UTF-8)" and then click "Next."
Enter a name for the converted .CSV file, choose where you want to save it and then click the "Export" button.