I've often been asked about how to delete WMI classes, so here's the best way to do it.
Use caution when deleting WMI classes as doing so can cause long term or unrecoverable issues.
Start by running WBEMTEST.

Click Connect…

Ensure the Namespace is root\cimv2 and click Connect.

Select Enum Classes...

Choose Recursive and click OK.

Once the list is fully populated, find the class you wish to delete; in this case I have chosen ES_MIR. Click Delete to delete the class.
Use caution when deleting WMI classes as doing so can cause long term or unrecoverable issues.