Citrix XenApp

My Citrix Blog and troubleshooting Information.

Citrix Down Sessions & Multiple Instances

Sorry to all the people who visit this sites that it hasn’t been updated for a while, I’ve been working on many projects with very tight deadlines, hence I haven’t had time to write here. I’ve closed the comments on this site now since I can’t be bothered with the spam.

Issue: Today I’m working on a problem a where a user sessions remains even when the user has logged off. The user is unable to launch a new instance since the session is still there just in a down state. If you allow more than once instance then you end up with multiple sessions or processes event though this are not visible to the end user.

Troubleshooting: Check the user’s session ID which is down and then open task manager, add the column “Sessions ID” and look for what process remains. If it csfss.exe it the same issue I’m having.

Environment: Citrix XenApp 6.5 on Windows 2008 R2 x64

Resolution: It looks to be a Microsoft Issue as per but it will be tomorrow before I can confirm.

UPDATE: Looks like this service pack doesnt apply to use since we have SP1 installed. I keep troubleshooting.

Citrix – The following requested video mode was not available

Today Issue: We have a Citrix display issue with XenApp 4.5 for Windows 2003 when launching an application on 3 screens at 1280 x1024. The message displays: The following requested video mode was not available 3840 x 1024 x 16 BBP. Video mode restricted by system administrator.







RESOLUTION: If you have made changes to registry to increase memory on Windows 2003 with Citrix XenApp 4.5 then you have set SYSTEM permission to deny as per instructions on other Citrix/Blog sites.

Check permissions of this key \HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\Wds\icawd\thin16 and allow SYSTEM.

Note: This does mean that if the farm settings are applied to the server propeties > Display any custom configuration will be lost. (see my other post on settings multi-monitor settings for 3 or more screens)

Information provided is based on issues I encountered and resolved, this solution may not be for everyone.

OS: Windows 2003 x64 R2

Citrix: XenApp 4.5


Citrix XenApp: This network connection does not exist

Today I ran into an issue with a recently deployed Citrix farm, which has been in use for the last couple of weeks.
I’m receiving the error “This network connection does not exist” when launching a single application. However when I change the published application to another server (B) it works fine. This message appears for all users this morning. We have 2 XenApp 5.0 FP3 servers in our farm, however when I (Domain Admin) tried to launch it on server A it worked fine. I tested again with one of the users and still had the same message.
I then duplicated the application instance and called it a new name and didn’t change any other settings apart from the server group and added server A. The user could then launch the application from server A under the new published instance. In fact the user could launch from both Server A and Server B.

I tested this a few more times with the user, both published applications point to the same location, have the same users, etc..

So it appears the problem is with the application named instance and could be a DB issue, but how can I be sure?

Now my users are happy again, I will create a test user and try to replication the problem.
A good tool for this would be Process Monitor by sysinternals, (Now Microsoft). This shows all the processes, files, and registry entires for a single user. I will be looking for permission issues or invaild entries.
More information on this subject can be found on the Citrix forum:

Terminal licensing server not issuing licenses

OS: Windows 2003 x64 R2

I spent the best part of my morning yesterday trying to figure out why my terminal licensing server isn’t issuing license. At first I thought there was an issue with the license server so I reactivated it with Microsoft. Still not issuing licenses?!!?

Well, here’s an interesting fact! Windows 2003 licensing server doesn’t monitor or decrement per user licenses. This means you have to guess how many licenses you need, but as its unmonitored terminal services won’t prevent you accessing the server if you go over your purchased amount.

If you configure Per Machine licensing mode the server will issue those license and time stamp them for 3 months.

In Windows 2008 Microsoft monitor per user licenses!

Also see Microsoft article

Citrix XenApp Multi-Monitor Issue

The  issue: Today I was asked to investigate a problem with users that were unable to move their Citrix Session to another display (monitor).  At first I’ve been told this was an issue with Windows 7, but it is not the case.

The enviroment:

OS: Windows 2003 X64 Enterprise

Citrix: XenApp 4.5 with Feature Pack 2

Workstation: Windows 7 with 3 display at 1280×1024

The reason:

There’s an session memory limitation on the maximum number of screen vs screen resolution and colour depth.


The default farm setting for user sessions is 5124KB which is fine for a single display of 1280×1024 at 16Bit colour depth. However using a second screen at this resolution and the user will not be able to move the Citrix window to another screen. We have increased the client sessions to 8194KB which is the maximum Citrix setting and now users can now have 2 displays at 1280×1024 at 16 bit colour depth, but not 3 displays!

Here’s the workaround and it works in most environments, I’ve worked on.

For up to 8 monitors 1280x 1024 24Bit you need make a change the system registry: (Please backup your registry before hand!)

The first step is to uncheck “Use Farm Settings” in your Citrix Management Console (Delivery Services Console) server properties.

  1. Citrix Resources > XenApp > Name of Farm > Servers > XenApp Server (Right click Properties)










Checking this box again will undo the settings we are about to change in the registry.

Now we need to adjust the SessionPoolMemory to increase it to more than the restricted 8194KB Windows 2003 limit.

First Registry Change

Open your registry and Navigate to \HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management

Create DWORD: SessionPoolSize

Value: 80

Second Registry Change 

\HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\Wds\icawd\thin16

Change DWORD MaxLVBMem

Value: 1e00000

Now just reboot your Citrix server and test with your new settings.

This is a simple change that works for most installations I’ve worked on, but may not be suitable for your environment.

Please also refer to for more information and troubleshooting.

 LVB Calculation Spreadsheet

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