Known Issues with .Net 4 regarding Citrix XenApp and WebInterface

This article describes several issues and their known workarounds for Microsoft .Net 4 products that users must be aware of in conjunction with Citrix XenApp 4.5, XenApp 5.0, XenApp 6.0 and WebInterface 5.0 through 5.3.

Issue 1
Delivery Services Console or Access Management Console does not display all nodes. They only display search results if .Net 4 is installed prior to XenApp 4.5 or XenApp 4.5 with Hotfix Rollup Pack 5. (223240)

Workaround
Install or upgrade to XenApp 4.5 Hotfix Rollup Pack 6 rather than XenApp 4.5 Hotfix Rollup Pack 5.

Note: .Net 4 does not have to be re-installed after upgrading from XenApp 4.5 or XenApp 4.5 Hotfix Rollup Pack 5 to XenApp 4.5 Hotfix Rollup Pack 6 – OR – Install .Net 4 after XenApp 4.5 or XenApp 4.5 with Hotfix Rollup Pack 5.

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Issue 2
If .Net 4 is present prior to install of XenApp6 (Web Interface 5.3), or the creation of additional Citrix Web Interface Web sites after initial installation of Web Interface, then user cannot launch applications from Web Interface and “Unable to launch the requested resource…” error is displayed. Impacts – XenApp 6.0 (233933)

Workaround

Change path of every Citrix Web Interface site to point to .Net 2 dlls, rather than to .Net 4 dlls.
Launch Internet Information Services (IIS) Manager.
Select Citrix XenApp Web Interface site in the Sites tree. (Default – Web Site\Citrix\XenApp).
Select Handler Mappings.
Select each handler mapping starting with “CitrixWebInterfaceMapping-xxx-32 or 64”.
Note:
On 32-bit systems, there are three handlers for *.ica, *.inc and *.rad.
On 64-bit systems there are six handlers: 32-bit and 64-bit versions for each of the three file types.
In the Executable text box, change the path to point to your .NET 2.0 ASP.NET ISAPI DLL
(sample default path – %windir%\Microsoft.Net\Framework\v2.0.50727\aspnet_isapi.dll.
Select OK and close Internet Information Services (IIS) Manager.

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Issue 3
When users try to connect to the XenApp Services site using Citrix Online Plug-in, they receive the following error message when parsing the config.xml file:

“Citrix XenApp could not contact the server entered. This may be because the server is down, there is an error in the configuration file from the server, or the details entered are incorrect. Please try again.”

- Or -

“Citrix XenApp could not contact the server. Please check your network connection”

From the IIS logs, you might see HTTP 404 errors:

2010-09-19 04:26:22 ::1 GET /Citrix/PNAgent/config.xml – 80 – ::1 C:\Program+Files\Citrix\ICA+Client\PNAMain.exe 404 2 1260 0

Cause
Microsoft .NET 1.1 and/or 4.0 Framework has been installed on Web Interface 5.x server.

Resolution
Two solutions to resolve this issue:

1. Uninstall .NET 1.1 and/or 4.0 Framework and create a new XenApp Services Site.
2. If you need to leave .NET 1.1 and/or 4.0 Framework for a third-party application on the server, follow the steps below to fix the already created site. Note: Any new XenApp Services site created, you would still need to perform this workaround unless you completely uninstall .NET 1.1 and/or 4.0 Framework from the server.

Workaround

• Open the IIS Manager console and go to the XenApp Services site created and select Handler Mappings:

• Open Handler Mappings and find these three entries: CitrixWebInterfaceMapping-dtd-32, CitrixWebInterfaceMapping-inc-32, and CitrixWebInterfaceMapping-xml-32. Note: For 64-bit servers, you will find the same entries mentioned above but with three more 64-bit entries at the end (see below).

32-bit Server Handler Mappings:

64-bit Server Handler Mappings:

• Change the executable aspnet_isapi.dll from .NET 4.0 to .NET 2.0.

Before:

After:

• After you click OK, you see the following prompt:

• Select Yes. Repeat the same steps for the remaining entries *.inc, *xml.)

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Issue 4
Applications fail to launch on a windows 2008 server when .NET 1.1.x or .NET 4.0 is installed on the Web Interface server. When the user clicks to launch the published application, nothing happens. The browser might briefly show a request, however, the Citrix ICA client never attempts to connect.

Background
It is currently suggested not to run .NET 1.1 or .NET 4.0 on a windows 2008 Web Interface server that is using Web interface 5.0 through 5.3. The .Net Framework 2.0 common language runtimes will be used in conjunction with the 3.0 and 3.5.

Troubleshooting
To confirm that this issue is occurring, the IIS logs will show the following response for the GET:

A 302 error will appear as a result of the launcher.aspx
A 500 error will appear as a result of the launch.ica

See examples below:

GET /Citrix/XenApp/site/launcher.aspx CTX_Application=Citrix.MPS.App.Farm1.notepad&CTX_Token=2FA544CAFAE53C3E0BC484529E48AD0C&LaunchId=1263341093875 80 – 10.7.82.11 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.1;+SV1;+InfoPath.2;+.NET+CLR+2.0.50727) 302 0 0 156 GET /Citrix/XenApp/site/launch.ica CTX_Application=Citrix.MPS.App.Farm1.notepad&CTX_AppFriendlyNameURLENcoded=notepad&CTX_Token=2FA544CAFAE53C3E0BC484529E48AD0C&LaunchId=1263341093875 80 – 10.7.82.11 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.1;+SV1;+InfoPath.2;+.NET+CLR+2.0.50727) 500 0 0 109

Workaround
Uninstall the .NET 1.1.x or .NET 4.0 Framework from the Web Interface server.

- Or -

Change the handler mapping for ica within IIS 7.
To change the handler mapping for IIS, follow the steps below:

• Open up the IIS Manager and highlight your Web Interface site’s virtual directory.
• Select the handler mappings icon under the features view and select open feature.

• Locate the CitrixWebInterfaceMapping -ica -32 and select to edit the one that has an “*.ica” extension under the path field.

• The incorrect executable path reflects .NET 1.1.x (or .NET 4.0) in use. Manually browse and modify that path to reflect .net 2.0.x.

Before:

After:

• Select Yes at the Edit Script Map notification.

• Run an IIS reset once the changes have been made.

Sources: CTX125635, CTX126692, CTX123921