When you are using NVIDIA GRID, you might know that NVIDIA started to activate license checking in Version 5.0. This means if no license is available, there are the following restrictions applied to the user:

1. Screen resolution is limited to no higher than 1280×1024.
2. Frame rate is capped at 3 frames per second.
3. GPU resource allocations are limited, which will prevent some applications from running correctly

Why ever NVIDIA has not enabled a Grace Period after a VM started – thus the restrictions are active until the VM successfully checked out a license. This has the effect that a user might connect to a just booted VM his session experience is limited. Furthermore, he has to disconnect and reconnect his session when the NVIDIA GRID license was applied to e.g. work with a higher resolution. Currently I know about three workarounds to fix this issue:

1. Change the Citrix Desktopservice startup to Automatic (Delayed Start)
2. Configure a Settlement Time before a booted VM is used for the affected Citrix Delivery Groups
3. NVIDIA Registry Entry – Available since GRID 5.3 / 6.1

Both workarounds have their limitations – thus I would like to show you both of them.

Changing the Citrix Desktopservice to Automatic (Delayed Start)

When you change the Service to an Automatic (Delayed Start) it will not directly run after the VM booted. This has the result that the VM is later registered at the Delivery Controller – it has time to check out the required NVIDIA license – before the Delivery Controller will broker a session to the VM.

To change the service to an Automatic (Delayed Start) open the Services Console on you master image (Run => services.msc) and open the properties of the Citrix Desktopservice. Change the Startup type to Automatic (Delayed Start) and confirm the change with OK.

Now update your VMs from the Master Image and that’s it. The VM should now have enough time to grab a NVIDIA License before it registers to the Delivery Controller.
The downside of this approach is that with every VDA update / upgrade you need to configure it again. Instead of doing this manually you can run a script with the following command on your maintenance VM before every shutdown. This command changes the Startup type – you cannot forget to change it (Important: There must be a space after “start=”).

sc config BrokerAgent start= delayed-auto

In a PowerShell the command needs to be modified a little bit:
&cmd.exe /c sc config BrokerAgent start= ‘delayed-auto’

Configure a Settlement Time before a booted VM is used

Alternatively, you have the possibility to configure a Settlement Time for a Delivery Group. This means that after the VM has registered to the Delivery Controller no sessions are brokered to the VM during this configured time. Again, the VM has enough time to request the necessary NVIDIA license. Howerver, this approach also a down side – if no other VMs are available users will still be brokered to just booted VMs although the Settlement Time did not end. This means if you didn’t configure enough Standby-VMs to be up and running when many users connect they still might be brokered to a just booted VM (without a license).

To check the currently active Settlement Time for a Delivery Group open a PowerShell and enter the following commands:

Add-PSSnapin Citrix*
Get-BrokerDesktopGroup –Name “DELIVERY GROUP NAME”

Replace the Delivery Group Name with the Name of the Delivery Group you would like to check

You now get some information’s about the Delivery Group. The interesting point is the SettlementPeriodBeforeUse in the lower area. By default, it should be 00:00:00.

To change this Time enter the following command:

Set-BrokerDesktopGroup –Name “DELIVERY GROUP NAME” –SettlementPeriodBeforeUse 00:05:00

With the above setting, the Settlement Time is changed to 5 Minutes – do not forget to replace the Delivery Group Name with the actual one.

If you now again enter the command to see the settings for your Delivery Group you will notice that the SettlementPeriodBeforeUse was changed.

NVIDIA Registry Entry – Available since GRID 5.3 / 6.1

With GRID Release 5.3 / 6.1 NVIDIA has published a Registry Entry to also fix this. The description is a little bit limited but when I got it correct, it changes the driver behavior – thus that all restrictions are also gone when the license was applied after the session was started. Before you can add the registry setting, you need to install the NVIDIA Drivers in your (Master-) VM and apply a NVIDIA License. When the license was successfully applied, create the following Registry Entry:

Path: HKLM\SOFTWARE\NVIDIA Corporation\Global\GridLicensing
Type: DWORD
Name: IgnoreSP
Value: 1

After creating, you must restart the VM (and update your Machine Catalogs if it is a Master-VM). Honestly I wasn’t able to test this last solution by myself – so I can’t tell if this really fixes the issue all times or only mostly….

That’s it – hope it helps (and NVIDIA will completely fix this issue in one of their next releases).