http://blogs.technet.com/virtualworld/archive/2008/09/02/interesting-issue-with-app-v-rc-build-4-5-0-1308-and-additional-management-server-failed-to-establish-a-connection-to-the-data-source.aspxThis is quite interesting and is fixed in the RTM release but whilst your testing your RC releases of App-V its worth whiling knowing about this gotcha that can occur! as it has caught a couple of my customers out. So lets consider that we want multipleen-USCommunityServer 2.1 SP1 (Build: 61025.2)http://blogs.technet.com/virtualworld/archive/2008/09/02/interesting-issue-with-app-v-rc-build-4-5-0-1308-and-additional-management-server-failed-to-establish-a-connection-to-the-data-source.aspx#3117482Wed, 03 Sep 2008 21:56:06 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3117482App-V RC Build 4.5.0.1308 and Additional Management Server - Failed to establish connection to data source<p>PingBack from <a rel="nofollow" target="_new" href="http://www.ditii.com/2008/09/03/app-v-rc-build-4501308-and-additional-management-server-failed-to-establish-connection-to-data-source/">http://www.ditii.com/2008/09/03/app-v-rc-build-4501308-and-additional-management-server-failed-to-establish-connection-to-data-source/</a></p> http://blogs.technet.com/virtualworld/archive/2008/09/02/interesting-issue-with-app-v-rc-build-4-5-0-1308-and-additional-management-server-failed-to-establish-a-connection-to-the-data-source.aspx#3126085Fri, 19 Sep 2008 16:20:29 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3126085George Potts<p>Using the RTM bits I found that enabling the TCP/IP protocol for the local SQL Express install also worked without adding that account. &nbsp;(Be sure to restart the SQL Server service.)</p>