Category: Citrix

Citrix Xenapp Published Desktop screen flickering

This issue might be caused by a setting in Internet Explorer for Remote Desktop/Terminal Service. Try this to solve the issue.
1. Open Internet Explorer and go to Tools > Internet Options
2. Go to Advanced tab and look under Browsing > Force offscreen compositing even under Terminal Services. untick this option.
3. Restart your Internet Explorer




Remote Desktop IP Virtualization doesn’t work

Remote Desktop IP Virtualization

Remote Desktop IP Virtualization is a new feature introduce in Windows Server 2008 R2  which provides administrator the ability to assign unique IP to a session or a program which requires it.

By default, IP Virtualization requires a functional DHCP to be use as an address pool source but we can also define a static IP address range as the IP Pool (


During my Desktop Virtualization project, we had an application which can’t run on a multi-session environment and we would like to test whether by enabling IP virtualization can help to solves the issue. We have enabled and configured IP Virtulization based on the article in technet ( and after perform a testing, we can’t see the leased IP.

The expected result should show a multiple IP on a single interface as the screenshot below.

Root Cause

A case has been open to Microsoft, and it seems like it was caused by the 32bit version of Sophos Antivirus Client. Uninstall it and the problem goes away. 🙂

Applicable to:

  • Windows Server 2008
  • Windows Server 2008 R2
  • XenApp 6.5

Additional Reference


ICAClient error on Ubuntu

I know some user will get this error. I’m writing this as a reminder to myself as well as sharing the solution with other people.

If you getting the error below, here is the steps to resolves this (

“You have not chosen to trust “ Secure Server Certification Authority:, the issuer of the server’s security certificate’.”

Note: there is an additional step that I need to configure on my machine, which is chmod +r to the cert under the keystore\cacerts\ folders.