I get an error There was a problem acquiring a personal certificate required to sign in. If the problem continues, please contact your support team. I'm using Windows 7 and have an office 365 account which is where Lync is hosted.

I've tried all the troubleshooting and no joy, also doubled check if there is a Lync certificate in the personal store, and none located.

See original post http://community.office365.com/en-us/f/166/p/289095/882945.aspx#882945

• Edited by BuddyHome Thursday, January 22, 2015 9:39 AM

Hi buddyHome,

The following steps should be able to resolve your problem.

1. Delete the sign in information.

Click Delete my sign-in information and Lync 2013 will automatically remove any saved password, certificates, and connection settings for the user account.

2. Delete the Lync User Profile and Registry Key.

User profile:

%userprofile%\AppData\Local\Microsoft\Office\15.0\Lync\sip_UserName@Domain.com

Registry Key:

HKCU\Software\Microsoft\Office\15.0\Lync\UserName@Domain.com

3. Revoke the client certificates on Lync Server

Run the following command in the Lync Management Shell:

Invoke-CsClientCertificate Identity UserName@Domain.com

If the issue still exists, please feel free to let me know.

Best regards,

Eric

• Edited by Eric_YangKModerator Friday, January 23, 2015 6:02 AM

Created a new profile and got the same problem. I gave up so re-installed windows and now problem solved.

• Marked as answer by BuddyHome Monday, January 26, 2015 11:09 AM