OS X 10.7.2 and Lync for Mac 2011, crash on start (how to fix it)

October 12th, 2011 at 6:28 PM  8 Comments

This isn’t exactly “news” but I figured I’d post it here anyway. There are probably only going to be a handful of people this problem and fix applies to, but those people will appreciate this.

My company uses Microsoft Lync for IM, presence, soft phone, etc. Most of the company runs it on Windows, but I had to be different and use a Mac. After installing the Lion update that was rolled out today, 10.7.2, the recently released Microsoft Lync for Mac 2011 client would not work, it simply crashed at login. Oddly enough the rather crash happy Office Communicator for Mac worked fine. A quick Bing around the net (thought I’d say Google, eh?) showed that I was not the only person suffering from this problem, and that 10.7.2 beta testers have been complaining about this for the last two weeks. After poking around, I noticed a certificate in my keychain marked as “Unknown” … removing it fixed my Lync issue.

So, go to Keychain Access and search for Unknown, delete it, enjoy Lync again.

  • THANK YOU!!!!

  • Thanks, just downloaded and tried to run it and got the same thing.  Deleted that unknown keychain and it fired right up.  Thanks a ton!!!

  • Nice catch.

    Deleting the unknown certificate worked for me too.


  • Michael, I added your blog url as a 3rd option to my post. I’ll update it as I hear more as well if you hear of other items let me know.
    Tom Laciano

  • Andrew Shay

    Any solutions to IMail crashing/not opening after 10.7.2 update?  Been a very frustrating day, and not hearing much about this one..

  • Very nice catch, thanks.

  • Shahzad Malick

    I just installed Lync on my Mac Lion and no luck with logon. Any help will be appreciated.