Recently, all user accounts (even including domain administrators) are unable to make changes to the (audio) volume level via the volume notification icon in the taskbar. Clicking on it does not prompt any response. The only way to make changes seems to be to login as the local admin and mute, unmute, and/or raise or lower the volume level for the system, which will then remain set for all users.
This is not an intended outcome and is an issue as the machines affected are for use by university users who often want to listen to music while they study or need to watch lectures with audio but cannot.
Could this be related to a group policy for the notification icon or some other GPO?