According to the System Requirements for Symantec Endpoint Encryption 11.3.x Client, the Endpoint Encryption client is not supported on VMware ESXi 6.5 hosted virtual machines but only on these VMware ESXi virtual machines:
This is correct. Endpoint Encryption is not officially supported with virtual machines hosted on VMware ESXi 6.5. Endpoint Encryption may work on virtual machines hosted on VMware ESXi 6.5 but
Symantec is committed to product quality and satisfied customers. This Feature Request is currently being considered by Symantec to be addressed in a forthcoming version of the product. Technical Support filed a Feature Request to add this product feature. Note that a feature request is exactly that, a request. There is no committed date for this request from the Endpoint Encryption Product Management team, nor from the Endpoint Encryption Engineering team at this time.