Duplicate Devices in USM when using Discovery Wizard and vmware

Document ID : KB000057252
Last Modified Date : 25/04/2018
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When the following conditions are met, you may see duplicate devices even when matching MAC addresses are present and IP + origin are matching between the devices.
  • You are discovering a Windows virtual machine with Discovery Wizard using WMI
  • You are using the vmware probe to discover the ESXi host that the guest resides on
VMWare actually provides 2 different UUIDs for each virtual machine and the vmware probe is capable of referencing and publishing either one depending on how it is configured.

The vmware probe references the instance UUID by default, but at the moment, discovery_agent references BIOS UUID. ?Since this virtual UUID is a very powerful correlator, this causes a decorrelation routine to be run, even though the devices may have correlated based on other factors.

A very short term workaround is to configure the vmware probe to reference the BIOS UUID in order to ensure that both probes are on the same page, however there are caveats that should be known. 

This issue is known to affect UIM 8.31 with vmware 6.53, however the issue will be present in older versions of the product as well since these routines have been in place for some time.


There is now a version of discovery_agent that will not publish the virtual machine UUID. ?Please contact support for access to this build.

Previous workaround
To configure vmware to reference BIOS UUID
  1. Open raw configure for the vmware probe
  2. Locate the use_instance_uuid key
  3. Change the value to: no

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