Lync 2011 for the Mac has had a troubled start for a lot of folks including myself. Right after the product RTMs Apple releases a major OS update, along with the requisite media blitz and tons of folks update. Troubleshooting an effectively brand new product along with a major OS update is an IT perfect storm. Of course asking Mac users to not update can be done, if you do not mind being ignored
Unfortunately for me Lync 2011 refused to work even after that fix. Lync would start, login, and promptly crash. The EXC_BAD_ACCESS error I received is well documented here.
Graciously Tom Laciano worked with me to get to the bottom of whatever was ailing my Lync installation. Right when we were ready to escalate the case to Microsoft Support, I found the following article: http://ucken.blogspot.com/2011/03/enterprise-voice-and-communicator-for.html
So here is what finally fixed Lync 2011 Mac working on my Mac Lion 10.7.2.
If you have Outlook 2011 installed, you HAVE to configure it to use your Exchange account otherwise Lync will crash. I use Outlook Web Access (OWA) instead of the Outlook client, so it never dawned on me that Lync would need Outlook since Communicator Mac clearly did not.
1. Setup your Exchange Account in Outlook 2011 and make sure it’s connected. BTW I did not have to wait for Outlook to finish downloading email to continue.
2. Trash your Documents\Microsoft User Data\Microsoft Lync Data folder. Lync would crash too quickly until I removed this folder.
3. Start Lync and login
4. Once Lync logs in immediately go to Lync->Preferences->Account and uncheck “Use Microsoft Exchange for managing personal information”
5. At this point my Lync was stable!
I am sure in a future point release Microsoft will improve the error checking here and handle this situation better. But for now this fix is working for me and I finally get to use Lync 2011 Mac!!!
UPDATE 12/28/2011: I am running Mac Office 2011 14.1.3
UPDATE: 1/15/2013: The *REAL* fix for this is here: http://ocsguy.com/2012/05/19/lync-phone-edition-connection-to-microsoft-exchange-is-unavailable/. Looks like the Lync 2011 Mac also needs the proper Exchange root certificate.