1) SEP 12.1.6 MP3 is already installed on client with all components ( AV, PTP , NTP ) full protection for client.
We export a new 12.1.6 MP3 package , however we removed the Outlook scanner from features and push this newly exported package to the client , would it overinstall the new package on existing package or it will be rejected by client becuase it is already running on the same 12.1.6 MP3 version.
while creating the package create a custom install settings with Remove all previous logs and policies, and reset the client-server communication settings checked and customer install featue set to rmove the outlook scaner.
Note: if that is the only component you want to modify, you can also disable it by policy.
2) what is the best method to remove the existing version of SEP and then install a newly exported package cleanly via the remote method either via the SEPM or SCCM. Are we required to use any script to achieve that ?
I would suggest you to go ahead with SCCM as you will have more control over the installation. Yes you may be required to install with a custom script to remove the existing version first.
3) when we run intelligent updater on the client running 12.1.6 MP3 it fails , in the log we are seeing the following message . SEP Agent is installed on default directory.
Ignoring entry for VIRSCAN.zip because of registry read failure. Error occurred while reading the path for the Authorization DLL from the registry.
The product corresponding to this entry in iuconfig.xml is not installed on the system.
can you post the enite log so that we can see what is happening.