Consider the following scenario:
Active Directory Federation Services (ADFS) is deployed on-premises in a Microsoft Lync Server 2013 environment.
You log on a computer that is running Microsoft Windows 7 by using an on-premises account in the environment.
You enable the DisableNTCredentials key in the following registry path:HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Communicator\
You try to sign in to Microsoft Lync 2013 by using a Microsoft Office 365 account on the computer.
In this scenario, you can’t sign in to Lync 2013.
This issue occurs because Lync 2013 doesn’t pass the Office 365 credentials to ADFS.
Note Lync 2013 passes the on-premises credentials to ADFS.
To resolve this issue, install the following update:
2825630 Description of the Lync 2013 update: September 20, 2013