Microsoft Lync 2010 Certificate Error


Recently, one of my co works came to me saying that the Microsoft Lync was not connecting and they couldn’t figure out why. They continued to explain that it was working fine the day before but when they powered up the computer today, they couldn’t connect. I figured that the problem was something simple such as entering the wrong user name or password and it would only take a few minutes to resolve.Lync Cert Error

Keep in mind that a lot of people rely heavily on the Microsoft Lync application to communicate with fellow employees. Instead of sending emails back and forth, the instant messaging function within Lync allows someone to instantly see the person’s status and send instant messages back and forth.

I took a quick look at her computer and verified that the username and password are correct by connecting to her account on my computer. I thought to myself, it’s not the account so it must be the computer. To verify my theory, I attempted to connect using my account on her computer, and to my surprise, I connected. It was about this time I was now confused and began to look into this in more detail. So I reverted back to the old saying “When all else fails, read the instructions.”

The error message that was being displayed said “There was a problem acquiring a personal certificate required to sign in.” Being the smart IT person I am with a vast library of knowledge at my fingertips, I googled the error, and came up with several possible causes and solutions for this error. I began to eliminate each possible cause and decided that I would actually check the certificate on the computer. I noticed that the certificate had actually expired the day before which was when she said it actually worked. Not that I found the cause, I just need the solution.

I tried to manually renew the personal certificate that had expired, but the renewal request failed. I then continued to remove the expired certificate, re-establish the connection back to the Lync server, and everything was back up and running. I won’t go into the details about certificates at this time, I’ll leave that for another article. For those that might experience the same problem, I’ve decided to include the process I used to access and remove the certificate below.


Solution:Cert Manager

Microsoft Lync 2010 Certificate Error

Cannot sign in to Lync “There was a problem acquiring a personal certificate required to sign in.”

  • Run cert manager on the computer that is having the issue connecting to Microsoft Lync by clicking on start and entering “certmgr.msc” in the search bar and hitting enter.
  • Expand Personal, and then expand Certificates
  • Double click on the user’s personal cert and check the date on the cert. In my case the certificate was expired which was causing the problems that I encountered.
    Cert Date
  • Right click on the certificate, and select delete to remove the expired personal certificate.
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