I am running a mid 2011 iMac with OS X 10.8. The addresses have all disappeared from the Contacts application. This happened in three separate stages: (1) I opened the application, which originally had about 100 addresses in it and found that only 20 were left; (2) a few hours later I reopened the application and found that only six addresses were left, and finally (3) when I opened it the next day all were gone. I have a SuperDuper back up, on an external HDD and the addresses are all missing from it as well. I also have of some of the addresses in an older Snow Leopard backup, but I would prefer to restore all the addresses which were originally on my current Contacts application. I have looked at various solutions on other websites, but not found any which solve my problems. I have two questions. (1) What can I do to find and eliminate the cause of the gradual deletions of the addresses? (2) Once that is done, where should I look to find (hopefully) the deleted addresses, so that I can restore them to the Contacts application?