If you try to install XenServer (and this probably happens with some Linux distros too) after having VMWare ESXi (vSphere Hypervisor) on your server then you’ll likely encounter an error early on in the installation process saying “Could not parse sgdisk”
This is related to how VMWare provision the disks for VMFS, as XenServer will error when trying to detect the local disks (it’ll check the partitions and see something completely unexpected) which I found out on the Citrix forums.
Easiest way to solve this is to wipe the partition table on the drive(s) using Darik’s Boot and Nuke. Set the drive(s) to the Quick Wipe method and let them run a few percent. Hard power-off the server and start again with your XenServer install.