Customer can disable the webclient during the OpManager Server Startup by modifying the file Opmanager_processinfo.xml under <OpManager>\\conf folder.
look for this line
<COMMAND Name="StartOpManagerWebClient" Type="InvokeClass">
<![CDATA[com.adventnet.me.opmanager.start.ShowClient]]>
<ADDITIONALPARAMS ParamName="InvokeClientCommand" ParamValue="cmd.exe /c start"/>
</COMMAND>
and change it to
<!--
<COMMAND Name="StartOpManagerWebClient" Type="InvokeClass">
<![CDATA[com.adventnet.me.opmanager.start.ShowClient]]>
<ADDITIONALPARAMS ParamName="InvokeClientCommand" ParamValue="cmd.exe /c start"/>
</COMMAND>
-->
and also look for
<PROCESS Name="StartOpManagerWebClient">
<COMMAND Name="StartWebClient" Type="InvokeClass">
<![CDATA[com.adventnet.me.opmanager.start.ShowClient]]>
<ADDITIONALPARAMS ParamName="InvokeClientCommand" ParamValue="cmd.exe /c start"/>
</COMMAND>
</PROCESS>
change it to
<!--
<PROCESS Name="StartOpManagerWebClient">
<COMMAND Name="StartWebClient" Type="InvokeClass">
<![CDATA[com.adventnet.me.opmanager.start.ShowClient]]>
<ADDITIONALPARAMS ParamName="InvokeClientCommand" ParamValue="cmd.exe /c start"/>
</COMMAND>
</PROCESS>
-->
Save the file. Stop and Start Opmanager