Article ID: 2560097 - View products that this article applies to.
Consider the following scenario:
This issue occurs because a flag is not set when you select the Do not join audio option. Therefore, an AppInvite message is not sent. The flag triggers the behavior that the Lync 2010 application layer adds audio modality to the AppInvite message when you join a conference without any modalities.
To resolve this issue, install the following cumulative update:
(http://support.microsoft.com/kb/2571543/ )Description of the cumulative update package for Lync 2010: July 2011
If the Join Meeting Audio dialog does not appear, you can follow these steps to change the default audio choice.