Hi,
KB4566425 is servicing stack update, it make changes to how updates are installed and cannot be uninstalled from the device.
Cmipnpinstall.dll is the PNP plugin installer for CMI.
You don’t find it since it’s a system and hidden file. Cmipnpinstall.dll is usually located in the %SYSTEM% folder.
If you can locate the extracted "Cmipnpinstall.dll" from the KB4566425 Update.
You can replace the old file with the newer version.
Hope above information can help you.
---Please Accept as answer if the reply is helpful---