Unable to Add vCenter or Refresh Virtual Machines due to Duplicate UUIDs


When adding a vCenter Server to the Unitrends appliance, the following error is presented "ESX servers ESX1, ESX2 and ESX3 have the same UUID".



To alert customers that UUIDs of ESX Servers may not be unique if they are not set by the ESX Server manufacturer. This would not allow the customer to add the vCenter Servers to the Unitrends appliance or refresh/reload the list of Virtual Machines existing in the VMware inventory.


When adding a vCenter Server to the Unitrends appliance, following error comes up –

ESX servers ESX1, ESX2 and ESX3 have the same UUID.
Refer to Unitrends article Unable to Add vCenter or Refresh Virtual Machines due to Duplicate UUIDs for possible steps to resolution.

This happens because 2 (or more) ESX Servers in the vCenter have the same hardware UUID. This error also comes up if a vCenter is added successfully to the Unitrends system and later an ESX Server is added with a duplicate UUID and then, a “Refresh of Virtual Machines” is performed.


This occurs because the hardware manufacturer of the ESX Server didn’t set the ESX UUID. As per the guidelines provided by VMware, Unitrends uses this UUID to differentiate between ESX Servers. If this is not unique, then the above error is seen.



To confirm that 2 ESX Servers have the same UUID, following steps can be performed in a browser –

  1. Go to  https://<host>/mob/?moid=ha%2dhost&doPath=hardware%2esystemInfo and enter the vCenter credentials when prompted.
  2. All the clicks from here on are in the right-most columns and the terms referred are in the leftmost column
  3. Click on ‘content’
  4. Click on ‘rootFolder’
  5. Click on ‘childEntity’ – Here there will be all the Datacenters in the vCenter inventory. All these need to be traversed.
  6. Click on ‘hostFolder’
  7. Click on ‘childEntity’ – All the ESX Clusters will be displayed here. If there are no ESX Clusters in the environment, then, there will be only one entry here
  8. Click on ‘host’
  9. Click on ‘summary’
  10. Click on ‘hardware’
  11. Note the ‘uuid’ row. It would have an entry like – “00020003-0004-0005-0006-000700080009”
  12. Go to Step 8 and perform the Steps 9 to 11 for the remaining ESX hosts in that ESX Cluster.
  13. Go to Step 7 and perform the Steps 8 to 11 for the remaining ESX Clusters in this Datacenter.
  14. Go to Step 5 and perform Steps 6 to 13 for the other Datacenters.
  15. In all the above steps there will be more than one ESX Server having the hardware UUID as pointed out in Step 11

Once the UUIDs are confirmed, the hardware vendor should be contacted for the resolution, since this UUID needs to be setup by them.

NOTE: If the hardware UUID is not “00020003-0004-0005-0006-000700080009”, but there are still duplicate UUIDs for any ESX Servers, still the hardware vendor should be contacted, since this entity is supposed to be unique.

Third-Party Sources

VMware - http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006250

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