There is one registry patch that needs to be applied to each Citrix client. In recent versions of Citrix, use of custom virtual channels must be explicitly enabled via this registry patch. If the patch is not applied, communication between client and server is not possible. This patch can be applied without modification. For x86 clients, RegPatch allows custom virtual channels in ICAClient.reg. For x64 clients, RegPatch allows custom virtual channels in ICAClient x64 Client.reg. These files are installed as part of the Citrix Server component installation.

RegPatch installs startup programs on Citrix Server.reg. (RegPatch is the registry patch that is applied to the Citrix Server.) This registry patch designates an executable file as a startup program that is launched along with a Citrix-published application. This patch is edited to reference the full file system path to the Microsoft.Uii.Csr.CitrixIntegration.exe server component.

To install the patches

1. Run the RegPatch Allow Custom Virtual Channels in ICAClient.reg key. This is available in the base directory where the Customer Care Accelerator (CCA) Citrix component is installed on the Citrix Server ([Install directory]\Microsoft Uii\Citrix Server Component).
2. Open Registry Editor (Regedit.exe) and navigate to Computer\HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Terminal Server\Wds\Icawd.
3. Make sure the startup programs point to the correct location of the Microsoft.Uii.CitrixIntegration.exe file.