Version: 4.3 (using 4.3.2 (KDE 4.3.2), Debian packages) Compiler: cc OS: Linux (i686) release 2.6.31odino Kaddress book deleted all my contacts. Last thing i did was delete the blank contacts it creates time to time (i am afraid i didn't fill a bugreport for that). And i don't remember if i killed kontact with kill (since sometimes it closes the window but doesn't terminate and doesn't start again). I am afraid i can't offer much more details but it is quite annoying (and i would be much more mad if i didn't have a recent backup).
Thank you for your efforts you put into this bug. kab3 has long been deprecated, and so I close its old reports. If this bug/wish is still valid for kab3's successor kaddressbook in any recent version (5.0 or later, as part of KDE Applications 15.08.0 or later), please file a new bug against kaddressbook.