Or why Microsoft killed the ConcurrentUserSessions setting in the new FSLogix versions and why you (probably) never needed it anyway...
Often I would see this set as part of an FSLogix deployment under the misapprehension that it is required on Server OS to make multiple sessions work. It's not required. It never was.
This setting doesn't exist any more. Let's talk about what it said originally and why Microsoft changed it.
Originally it said:
Enable FSLogix to handle concurrent user sessions on the same machine.
Note: If you are using the Windows server feature to allow concurrent logins for the same Windows account on the same server (seen most often with Citrix XenApp), you must enable this policy.
Most people seemed to have glossed over the part where it says "for the same windows account."
The ONLY time you want to use this is if you're sharing a generic account and everyone needs to log in to the same machine simultaneously with an individual desktop session.
This is a bit of an edge case but most commonly seen in manufacturing and sometimes healthcare. It's also sometimes in play with public kiosks.
You can't even do this by default in Citrix! You can't have multiple desktop sessions on the same machine with the same user because by default you'll get sent to your already established session on that machine, so you need to override many settings to even make this work.
FSingleSessionPerUser set to 0 is needed on the RDS side of things. This allows multiple sessions from the same user on the same machine. The default is that every user is limited to a single session.
On the Citrix side, you need to set session reconnection to disconnected sessions only and same endpoint only, otherwise it'll assume you're roaming the session and all new connections will go to the existing open session.
The wording around ConcurrentUserSessions has since been removed and so has the setting.
Hopefully this will stop people trying to configure this setting, but because the screenshots for the ADMX templates in the documentation still show this setting, people still ask about it.
It also gets mentioned indirectly in the What's New notes for the latest version:
99.9% of people never needed this setting and so Microsoft removed it from FSLogix and it now just checks if you've got FSingleSessionPerUser set to 0.
If you're one of the 0.1% that need this, please let us know why!
Mike Streetz, CTP, Los Angeles CUGC Leader