ESXi VM hardware versions 10 and 11 include a SATA controller for CD/DVD by default. If the SATA and SCSI controller are present on the PVS Target Device, the target will fail to boot. PVS relies on the SCSI controller, SATA is the only one that can be removed. To resolve this issue, change the Virtual Device Node for the CD/DVD Media from SATA to IDE and remove the SATA controller. This must be performed prior to installing the operating system.
To get around this do the following:
i) While creating a new VM from the vSphere web client, under Edit Settings > Customize hardware > Virtual Hardware, change the Virtual Device Node from SATA to IDE for CD/DVD Media.
ii) After selecting the corresponding IDE radio Button, the Remove option for New SATA Controller becomes active. Get rid of it by clicking the “X” at the right hand side of the New SATA controller line
Note: If the Virtual Machine is already created, the mentioned steps should be performed by going to Edit Settings -> Virtual hardware in the vSphere Web Client.
Found this type courtesy of http://support.citrix.com/article/CTX200969 – which also provided info on other issues relating to vSphere 6 and citrix products