Office For Mac

Lync for Mac crashes after Mac OS X 10.7.2 update

Hey Everyone,

The recent update to Mac OS X Lion (10.7.2) installs an invalid login certificate on most systems, which results in Lync for Mac crashing when it tries to sign in.

Until we get a software update out, there is a workaround that seems to be working for most users that we wanted to let you know about:

1. Open the utility Keychain Access – from Finder to go Applications and then into the Utilities folder. Or just search for it via Spotlight.
2. In Keychain Access – in the left pane click on “login” on the top, and “Certificates” on the bottom.
3. In the right pane, find a certificate with the name “unknown”. Select it and delete it. You may have to unlock your keychain with your password.
4. Close Keychain Access.
5. Restart Microsoft Lync.

This same workaround is also posted on the Microsoft Answers Forum if you would like additional information. Hope that works for you!


October 13th, 2011
Bookmark and Share
— @
  1. Pingback: Workaround for Lync for Mac Crashes on Mac OS X 10.7.2

  2. Augusto Ponce de Leon says:

    Thanks you! It worked for me

  3. Andre says:

    tested and approved!!!

  4. Jaco v/d Merwe says:

    Instantly resolved… thanks so much…

  5. Cristian Caprar says:

    Lifesaver :) I was wondering why Lync is suddenly crashing on me :( It works now, thanks!

  6. Jarrett says:

    Well, this fixed the crashing issue for me. So that’s one step closer!

    Unfortunately, I’m also having another issue, but it’s weird. I experience no problems when I sign-on from home or the guest wireless network at work. If, however, I sign-on from VPN or the company’s wired employee network, I get logged out after about 45 seconds.

    Any ideas? Any troubleshooting steps I can take?

  7. Roman V. says:

    Still doesn’t work for me using either auto config or manual config using I sent my logs to the support rep assigned to my case.

  8. Neil says:

    I’m experiencing the same issue as Jarrett – Lync works perfect when I’m off-net, but logs me out almost immediately when on my corporate network. Nothing jumping out at me from the logs. I wonder whether it could have something to do with me being configured for SIP softphone perhaps?

  9. Pascal says:

    This allowed me to get pass the crash, thank you very much !!

    Now I have another message telling me : “Cannot sign in because the server version is incompatible with Microsoft Lync. Contact your support team with this information.”

    Any idea ?


  10. Radhika Shetty_MSFT says:

    @Jarrett, Neil: If you are using Cisco/Juniper clients to get into your corp net, please note that currently there are issues using this clients with Lync. You cannot sign into Lync for Mac when you are connected through a Cisco or Juniper VPN client (

    @Pascal: Lync for Mac needs Lync Server 2010. Please confirm your server version.