Understanding the Error: Invalid session ID encountered

ERROR: Invalid session ID encountered

If you have a policy attached to a server, user-operated endpoint (device), or virtual machine and that policy has notifications configured, there is a chance that notifications will encounter this error in the amagent.log:

2022/07/29 11:50:24 notifications_windows.go:114: Notifier logs: INFO: Spawning notification process on active session

INFO: Enumerating sessions
ERROR: Invalid session ID encountered

2022/07/29 11:50:24 notifications_windows.go:123: Error reading output file: open C:\ProgramData\amagent\notify668106769\notify-output.txt: The system cannot find the file specified.

You can find the Amagent log here: Location of Files Required by Automox

Impacts of the error

Let's first explain the impacts of this bug before we understand what it is! 

When there are policies with installation or reboot notifications attached to Windows devices, it can require user-interaction with the notifications before the policies are able to run. This can lead to issues if people do not interact with them, especially if the "Missed Patch Window" feature is not turned on (Handling Missed Patches). 

Example:

A policy run happens at its scheduled time, but there's no one logged in to the server (a much more common scenario)! If the policy requires user interaction, it will generate this error in the amagent log, as there's no logged-in user to receive a notification. 

This is expected behavior from the Automox agent, it is not an error. But, there are two types of workarounds that could be applied.

1. Turn off Installation and Reboot notifications.
   • This works for servers, as they are not attended to and shouldn't require user interaction. We also recommend this as a best practice. This would work for virtual machines as well.
2. Turn on "Missed Patch Window".
   • This works for user-operated endpoints. If they're not logged in, it will initiate the policy run the next time the agent checks back in with the device. Please note: it will only attempt one patch run before its next scheduled patch run.