I'm going to focus on FireFox, but this question is for many apps.

I want to push Firefox latest upgrade to my workstations.

I currently have a Zenapp that is associated to workstations and is
configured to FORCE RUN as a secure system user. This works fine when
no user is signed on.

When there is a user signed on, the upgrade can be somewhat unreliable.
I want to modify this Zenapp to run only when there is no user signed

The problem is that HKCU and any user settings are unavailable when an
app is configured to run as a secure system user. So I can't simply
check for HKCU registry key existance, or environment variables. I
can't do this by time of day as we are 24/7.

Any ideas what I could use to determine if a user is signed on or not?