This is crazy ??? How come apple has not said any thing here ..... I also can not edit my contacts and this has been gooing on a long time since I upgraded to ML.
I can not delete or edit any of my contacts within the address book or contacts application on the Mac. I have tried everything everyone has said up here and way more. I can edit things with terminal and edit Kext and plist. so I realized I know it am doing. I just have not found the correct Avenue as of yet. It seems for whatever reason there is read only turn on somewhere in this application or its connected files.
I cannot find any trace of this read only element and had edited much of my operating system.
If I log into iCloud.com, I can add contacts, add photos to existing contacts, remove information from existing contacts but I cannot do this on my Mac. I am running the latest version of Mountain lion. when I edit things on iCloud, they show up almost instantaneously on my phone and on the contacts app on the Mac when the program is already open. So there's no communication issues there.
I really hope someone smarter than me can figure this out.
I'm going to see if I'm having the same problem on my MacBook, and if I am going to scream. But the point is not the MacBook but to use my desk with my Mac Pro.....
just to add a note, I tried removing iCloud from everything and just syncing contacts to iPhone, iPhone to computer. That not only crash iTunes sort of, but did not work. From what I can tell there is about five different checkboxes in various places that you have to turn off iCloud and turn on Contact syncing from computer to iPhone or iPhone to computer.