A known Apple defect in the Mac OS X 10.7 (Lion) Address Book framework can cause Cisco Jabber to become unstable and quit unexpectedly. Cisco Jabber disables this feature by default for 10.7 and later versions. If you enable the Address Book, it might cause stability issues. This defect does not affect the Address Book plug-in, which you can install separately, allowing you to dial using Cisco Jabber directly from the Mac Address Book if you have phone services deployed in your environment.
To install the Address Book plug-in, choose Cisco Jabber > Preferences > General and click Install Mac Address Book Plug-in.