The UUID of a host can be non unique on White box hardware.
For example:
00020003-0004-0005-0006-000700080009
Note: White box hardware is a server that is not included in the VMware Compatibility List but has supported hardware internally and is supplied by an OEM vendor.
The UUID is read by the ESX host from the SMBIOS. It can be viewed in the Managed Object Browser through the link:
https://<host>/mob/?moid=ha%2dhost&doPath=hardware%2esystemInfo
Where <host> is your ESX host's service console, IP, shortname or FQDN.
This UUID is not generated by VMware. It is unique to the hardware and is set in the BIOS by the vendor. The output of the dmidecode command may show other examples of missing data. For example:
[root@hostsvr03 root]# dmidecode | grep Version
Version: To Be Filled By O.E.M.
[root@hostsvr03 root]# dmidecode | grep Serial
Serial Number: 1234567890
Serial Number: 1234567890
Serial Number: To Be Filled By O.E.M.
Serial Number: To Be Filled By O.E.M.
Serial Number: To Be Filled By O.E.M.
To resolve this issue, contact the OEM vendor.
Note: This issue was reported against white boxes with the UUID set as all 00 or all FF. In these cases, a UUID is generated using the same algorithm as that used for the VMFS UUIDs. However, when the UUID is left at a default value that is not all 00 or all FF, VMware has no way to identify the UUID as invalid.