You're welcome. An alternative I've used to named pipes among processes of different privilege levels is to build the service to listen for custom commands sent to it. These are just integers, and the service maps those to pre-defined commands.

Then the only thing the user-mode application can send are just flags (integers) that the service has already pre-determined what it will do in response.

Here's an article: https://www.codeproject.com/Articles/24434/How-to-Write-Wind...

And here's a succinct example: https://stackoverflow.com/a/5805700