After installing the Windows 10 update, the loopback adapter for SPLM licensing no longer functions.
Windows 10 is officially and unofficially supported by none of the platforms we use, including AutoCAD pre 2016 and CADWorx pre 2017. Disclaimer aside, it is possible to run CADWorx on Windows 10 and even continue to use SPLM loopback licensing.
If you updated to Windows 10 from a previous version of Windows, use this procedure. During the update process, the driver for the legacy loopback adapter is wiped out, as it appears to be incompatible with Windows 10. Updating leaves the device settings in place, but without the driver, the device is missing from the list of available network adapters.
In Device Manager:
Use the Action Menu, choose 'Add legacy hardware'
Select the Microsoft KM-TEST Loopback Adapter.
Once the installation is complete, the missing SPLM Loopback Adapter will be restored to the list of network devices, all settings intact.