msiexec /i "C:\<Deploy>\Unitrends_Agent.msi"
where <Deploy> is the path of the downloaded agent
msiexec /quiet /l* "C:\temp\Unitrends.log" /i "C:\<Deploy>\_Agent.msi"
Where "C:\temp\Unitrends.log" is the full path location of the log file named Unitrends.log.
msiexec /quiet /uninstall "C:\<Deploy>\_Agent.msi"