How to get Sonar to scan this vst? (it use to scan. same computer, all of a sudden this error is happening.)

Try running SONAR as administrator

Yes, I get this with some Blue Tubes plugins, while running SONAR as an administrator. They seem to run fine, though.

Or move VST to non-system folder.
This is one of the reasons I don't store my VSTs (except for VST3s) under Program Files.

run as admin = yes
VST path = C:\vst
 
 

from:
Antares Help Desk
Error Message: "User Privileges Insufficient to Start a Low Level Driver"Modified on: Wed, Jul 19, 2017 at 4:12 PM

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This error occurs with Avox 4 plug-ins on Windows when the necessary iLok drivers are not installed.
 
Download the latest Avox 4 installer found here: http://www.antarestech.com/download/latest-software.php
Inside that folder, you’ll find an installer called "InterLok Driver Setup Win64.exe”
Run that installer, and restart your computer.

Did you forget to have the iLok dongle plugged in the last time you scanned your VSTs?