You encounter one of the following issues in a Microsoft Lync Server 2010 environment:
When you apply a client policy to disable the Activity Feeds tab in Lync 2010, the Activity Feeds tab is displayed and then disappears unexpectedly.
When a user who does not have Enterprise Voice enabled signs in to a Lync 2010 client, the Phone tab is displayed and then disappears unexpectedly.
Note These issues typically occur when network latency is high.
This issue is caused by a timing issue that occurs when Lync 2010 creates tabs.
To resolve this issue, install the following cumulative update:
2701664 Description of the cumulative update package for Lync 2010: June 2012
For more information about how to disable the Activity Feeds tab, go to the following Microsoft website: