Hi,
According to this KB : VMware KB: The Virtual Machine Automatic Startup / Shutdown feature in ESXi hosts in a VSA cluster gets disabled
Note: The Virtual Machine Start up and Shutdown (automatic start up) feature is disabled for all virtual machines residing on hosts that are in (or moved into) a vSphere HA cluster. Automatic start up is not supported
when used with vSphere HA. For more information, see the
Creating a vSphere HA Cluster section of the vSphere 5.1 Availability Guide.
You can check this previous post with the same subject : Re: Automatic virtual machine startup and shutdown option is disabled/greyed out
Regards,
Julien.