Problems with WMI sensors

I'm triying to monit basic stuff (memory, cpu ...) in my windows servers without an Admin account, had to do it because use an admin account for monitoring propouses it's against our security policy, i found out that WMI sensors had random behavior.

I have first triyed with your wmi tester and the account that we have created (WMI permissions configured) that the custom query:

SELECT DriveType,DeviceID,FreeSpace,Size,VolumeName FROM Win32_LogicalDisk WHERE DriveType=3

return correct values.

Then i add the WMI sensor to the configured device in my prtg and get "Code PE016 - No result set"

So as a digest the only WMI sensor that works for me it's Memory sensor even when i have tested that others must work. The test that i made with the wmi tester obviusly it's executed in the PRTG server with the same user etc ... triying to replicate the query that the PRTG it's making.

I need further information on how to make prtg works without a user with non Admin permissions.

Best regards.