How to move SEPM from C drive to x drive:
The best course of action in this situation would be to run a disaster recovery on the SEPM, and reinstall SEPM directly on another drive.
Here are the steps for your reference:
1. Disaster Recovery Process
>Disaster Recovery for SEP 12.1
http://www.symantec.com/business/support/index?page=content&id=TECH160736
Or use this KB in case you have an existing SQL Database
>Disaster Recovery for Symantec Endpoint Protection Manager 12.1.x with existing SQL Database
http://www.symantec.com/connect/articles/disaster-recovery-symantec-endpoint-protection-manager-121x-existing-sql-database
2. Uninstall Symantec Endpoint Protection Manager from the Server.
3. Restart the server.
4. Install the Symantec Endpoint Protection Manager on the desired Drive, using the same installation media version that you just uninstalled from the C Drive.
Note: The version of SEPM has to be the same which has been uninstalled recently.
Re install SEPM using a disaster recovery file. When the Management Server Configuration Wizard runs, choose Custom configuration and use a recovery file.
5. After the reconfiguration is complete, the SEPM Console will launch automatically. You should now be able to log in as you have always done using your security accounts. The Console should indicate that it is communicating and managing the clients that were being managed prior to the SEPM Move.
Note: Live Update component will always stay on the C drive, no matter what you do. However, LU downloads the content first to the C drive and then moves it to the other drive.