invalid class

Hello bclapperton 

The "invalid class" error is an error returned by the Windows Management Instrumentation. The cause can be different, and occurs at every installer that needs to access the WMI.

Here is a link that might help you to "repair" your WMI on the particular machine:

https://techcommunity.microsoft.com/t5/ask-the-performance-team/wmi-missing-or-failing-wmi-providers-or-invalid-wmi-class/ba-p/375485

Regards, 

Oliver