The Lync client for Apple’s OSX platform was released recently - much to a sigh of relief from most Apple users. While Communicator 2011 was ‘OK’ it was on OCS 2007 R2 experience, not Lync, and so felt like the poor cousin of your fellow Windows Lync users.

Anyways, I ran into a problem. On all of my Mac machines Lync just wouldn’t run - I’d fire it up, sign in, and bang, it would crash. Nothing in the crash logs indicated much. It’s been infuriating. My google skills on this issue were pretty weak - searching for Lync for OSX/Mac didn’t result with any useful posts as the client was so new.

So, with much gritting of teeth I set about trying to track it down. Built up a new OSX Machine in this order:

Lion 10.7.0 -> Worked

Lion 10.7.1 -> Worked

Lion 10.7.2 -> Borked

RIght, easy you think - it’s 10.7.2 right? Oh if only it were that simple. Essentially what I worked out was that if I logged in to a machine that had syncronised Keychains from another machine running 10.7.2 then bang, Lync wouldn’t run.

So, to be clear, this machine running 10.7.0 on new account - just fine. Log in to account with sync’ed Keychain from another machine running 10.7.2 and it didn’t work.

Got closer then….So, after much digging around in the Keychain, I noticed something a bit odd in certificates - namely an ‘Unknown’ certificate:

After checking a clean 10.7.0/10.7.1 account this was not there - it’s only there on 10.7.2 generated accounts. Guess what - delete it, and your Lync client will work just fine.

How infuriating is that?

Reblogging this.