What Registry Field does WMI Polling look for to populate Nodes.Contact?

As far as I know, SolarWinds does not populate the Contact field for any WMI-polled nodes. It is only populated when SNMP polling is used and it pulls the data from these registry entries in Windows:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\SNMP\Parameters\RFC1156Agent\sysLocation = Nodes.Location

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\SNMP\Parameters\RFC1156Agent\sysContact = Nodes.Contact

I tested manually putting data in the Contact field of a WMI node but the node rediscovery (default every 30minutes) overwrote this with a blank entry.

An alternative option would be using the SNMP contact field along with a node custom property that contains the relevant contact details. In the NPM alerting, reference both the SNMP contact field and the new custom property in the message. The alert message will contain contact information from either field (or both if they're both populated). If you are using them for email addresses you could put the variables in the To (or CC/BCC) field: e.g.  ${Node.Contact}; ${Node.WMIContact}.  It will populate with polled SNMP information and/or email addresses you have configured for your WMI nodes.  Note that the email address method may cause an issue for nodes that have more than email information in the field.

So verses Polling the Node for the "Contact" i would just use the Custom Fields (located in the same nodes table) for "WMI Contact" and populate it thru Solarwinds.

That works.  I would rather have the NODE tell me who the contact is, but this is a few boxes (Hyper-V) so manual process is fine.