When migrating a full Symantec Messaging Gateway (SMG) cluster, specifically a deployment involving a Control Center, Scanner, and Standalone Quarantine. The method of recovery significantly impacts system stability.
Instead of relying on a full database restore to "push" the old configuration to a newly imaged Standalone Quarantine, it is strongly advised to perform a fresh installation of the Standalone Quarantine.
Reinstall from Bootstrap: Perform a fresh installation of the Standalone Quarantine on the new hardware/virtual machine.
Add via Control Center: Add the newly installed Standalone Quarantine instance back to the Control Center via the web console.
For more details about configuring standalone quarantine, refer to the installation guide.