“Cannot sign in to Lync because this sign-in address was not found” error message during the Lync 2010 logon process when the default user is Lync-disabled

Symptoms

Consider the following scenario:

• User A is a Microsoft Lync 2010 disabled user. User B is a Lync 2010 enabled user.

• User A logs in to Windows and tries to log on to Lync 2010 by using the credentials of user B.

• User A types the credentials of user B incorrectly.

• User A clicks Sign In.

In this scenario, user A receives the following error message:

Additionally, user A does not receive the credential dialog box to type the credentials again.
This issue also occurs when Kerberos authentication is disabled, even if the credentials of user B are typed correctly.

Cause

This issue occurs because Lync 2010 handles the LCS_WRN_USER_NOT_SIP_ENABLED response incorrectly in the scenario that is described in the “Symptoms” section. Lync 2010 receives this response from the server when the request from Lync 2010 contains user credentials of a Lync disabled user.

Resolution

To resolve this issue, install the following cumulative update:  

2467763 Description of the cumulative update package for Lync 2010: January 2011

Status

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.