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Home > Success Center > Network Performance Monitor (NPM) > NPM - Knowledgebase Articles > Volume status is Unknown on VMs

Volume status is Unknown on VMs

Updated May 10, 2017


A volume on a VM with an Unknown status does not poll and there are duplicate volumes with the same mount point. 


  • All NPM versions
  • Virtual machine nodes


Windows assigns a serial number to every volume (for example: C:\ Label: 78b5bb82). If the virtual machine disk (VMDK) gets a full VMWare version, the administrator may change the size of the VMDK. When this happens, Windows interprets it as a new volume and assigns a new serial number. NPM uses the serial number from the VolumeDesc SNMP result to map drives in SNMP, so if the serial number changes, NPM also sees it as a new drive. This can cause the old drive to become "orphaned"  because it no longer exists on that host.


Remove the old drive and add the new drive via List Resources. This procedure cannot be automated. SolarWinds recommends VMWare administrators to notify the NPM administrator when the VMDK size is changed.




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