If the installation of the Endpoint Agent fails with the following error:
Installing MS XML 6 failed
You will need to install this update directly from Microsoft from
http://www.microsoft.com/en-us/download/details.aspx?id=9774
Once reinstalled, if the issue persists run the command:
msiexec /I CCNAgent_v2.03.3566.msi /q /Lv log.txt
Look inside log.txt for an error message that may be causing the issue.