Remko Weijnen's Blog (Remko's Blog)

About Virtualization, VDI, SBC, Application Compatibility and anything else I feel like

Archive for March, 2012

Cookie Error on Citrix XenApp

A user reported that the following error while visiting a website on a Citrix XenApp server:

You must have cookies enabled in order to user this tool. Please reload the page and try again.

I tried adding the site to the Trusted Sites List and adding the url to the Per Site Privacy list:


But this didn’t work, but I noticed that the site was “flickering” a lot so I suspected that HDX Flash Acceleration was the problem.


  • Filed under: Citrix
  • I needed to login as root on a Linux based virtual appliance to do some troubleshooting. In my case the appliance was running Suse Linux Enterprise.

    I booted the VA using the Ubuntu Live CD and opened a Terminal. Then I used the cfdisk tool (sudo cfdisk /dev/sda) to view the partitions:

    cfdisk /dev/sda


  • 1 Comment
  • Filed under: General
  • Create Active Directory Group with PowerShell

    If you want to Create an Active Directory group with PowerShell there are a few things you need to be aware of:

    First of all there is no direct way to create new objects in Active Directory. You always need to bind to the Domain or an Organizational Unit and call the Create method.


    However the group is not yet complete:

    Group name (pre-Windows 2000)


    When Launching a PowerShell script I noticed the following error: “AuthorizationManager check failed.

    AuthorizationManager check failed.| At line:1 char:2 | Microsoft.PowerShell_profile.ps1'

    This happens because either the Current User or the All Users PowerShell profile is empty.


  • Filed under: PowerShell
  • imageInteresting case today: customer uses Imprivate for two factor logon in combination with Citrix XenApp.

    Users reported that logons failed after they had changed their password. After contacting the users we learned that this only happened with special characters in the password like ! and +.

    imageTo do the actual logon to Citrix Imprivata uses an executable which is actually an AutoIT script compiled to an executable.

    After authentication the executable get’s the password from the Imprivata Appliance.

    I decompiled the executable to source and read the line that passes the password to XenApp:


  • 1 Comment
  • Filed under: General
  • Track who created the TreatAs registry key

    imageLast week I wrote about an error message the users received when opening documents from SharePoint.

    The article showed how to fix the problem but it didn’t feel good that I didn’t know where this “TreatAs” value was coming from.

    I figured that I could read the timestamp key from the registry to see at what/date time the value was created. This value can be read using the RegQueryInfoKey API but there are various tools that can read it.


  • Filed under: Other, RES
  • Lync Client Password Recovery

    I wrote a small tool that dumps all stored password for the Microsoft Lync Client that I’d like to share here.

    It’s a commandline tool that takes no arguments:

    Lync Password Dumper

    Have fun with it!

    Lync Password Dumper (8329 downloads )
  • Filed under: Lync
  • Today I was troubleshooting a message that appeared when a user tries to edit a document from SharePoint on a Citrix XenApp server.

    The user browsed to a word document on Sharepoint and selected “Edit in Microsoft Office Word” from the Combobox:

    Edit in Microsoft Office Word

    This would present the following error message to the user:

    'Edit Document' requires a Windows SharePoint Services-compatible application and Microsoft Internet Explorer 6.0 or greater.


    Running multiple instances of Lync (howto)

    imageYesterday I showed a video demonstrating it’s possible to run multiple instances of the Microsoft Lync 2010 client simultaneously.

    A little warning before we go on: the Lync Client was not designed to run with multiple instances. Or better said: it was designed specifically to prevent this, let’s see how it does this:

    On startup Lync calls an internal function called COcAppNoUI::InitializeMainInstance. In this function it creates a Mutex named “Office Communicator_” in the Global namespace. It also creates an Event in the Global namespace called “COMMUNICATOR-“.

    When a second instance of Lync is launched it checks if the Global Mutex exists and if it does it fires the Global Event. The Main instance has a thread that waits for this event using the WaitForMultipleObjects API.


  • Filed under: Lync, ThinApp
  • Run multiple instances of Lync 2010–POC

    This video shows that’s it’s possible to run multiple instances of the Lync 2010 client.

    I am running natively, so I am not using ThinApp or App-V.

    I will follow this up later with a how-to blog.

    Running Multiple Instances of Lync 2010
  • 1 Comment
  • Filed under: General
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