Posts

Citrix: Export to network drive really slow

For one of our customers I was asked to troubleshoot an application that exports data to several file types, including Microsoft Excel’s XLS file type.

Environment

The client runs Citrix XenApp 5 on Windows Server 2003 (x86). All user homedrives are mapped to the H-drive.

Problem

The application lets you perform queries on your Oracle database, analyze and format the results and prepare those for presentation. When the application exports an XLS-file to the H-drive, it freezes for 5 minutes and then responds normally again. However, when the same application exports a TXT- or CSV-file to the same drive, it freezes for just a few seconds.

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Change Tab Order in an Executable

An application called Cardiology PACS was recently packaged for a Citrix XenApp environment. The functional tester reported a strange problem at the logon screen: after entering the username it was not possible to go to the password field with the TAB key.

This was a strange observation since I cannot imagine XenApp interfering with tab stops. So what was going on?

In the old situation the user was starting the application on his local pc. The application remembered the last username and pre-filled this, therefore the cursor was already in the Password field. The user simply entered his password and hit the Enter key:

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On XenApp the Username field is not pre-filled because the last username is kept globally per machine. Therefore the user has to enter both the username and the password:

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I tested the Tab key behavior in both situations and as I expected it didn’t work in both situations. This happens because the Tab Order has been messed up by the programmer (if you press Tab 9 times you do end up in the Username field).

Because this is something that would annoy me if I were the user I decided to fix it.

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Application Hangs when Scanning in Citrix XenApp

Another interesting issue today with an application that runs on Citrix XenApp.

Environment
Customer has a Citrix XenApp 5 environment running on Windows Server 2003. Clients are all Windows XP and run the Citrix Online Plugin 12.3 full screen.

RES Workspace Extender is used to integrate locally installed application into the XenApp Session. Users have no access to the local desktop.

Symptoms
This particular application scans invoices using a USB scanner attached to the client and runs them trough a workflow.
Whenever the Start scan button was pressed the application froze.

SNAGHTML48ec098

 

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License Check fails on Citrix XenApp

imageA while ago I was asked to assist in getting an Excel Add-In to work on Citrix XenApp.

The application was packaged into a Thinapp by one of our package engineers.

However when testing the Add-In on Citrix XenApp the following message appeared:

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Apparently this application does a license check that fails when run from another server (how bad).

Disclaimer
Before we go on: I would like to make clear that my goal is not to be able to use an application without license. I am just trying to make it work within the customer’s environment.

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Modify VB Executable to force Taskbar Button

imageI had to troubleshoot an application that was published with Citrix XenApp. The problem with this application was that it didn’t have an button/icon in the taskbar and the window would sometimes disappear.

I noticed that this (cr)application was written in Visual Basic, so I decided to run it through a decompilation tool.

The decompiler was able to list the forms used in the Application:

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“Citrix Receiver – Security Warning” explained and demystified

Author : Ingmar Verheij

Citrix Receiver - Security WarningWhen you’ve worked with a Citrix XenApp or XenDesktop environment you must be familiar with the Security Warning dialog. It prevents a remote machine (your hosted application or desktop) from accessing resources on the client device, a security boundary you want to protect when from unmanaged systems.

But on managed systems you want to prevent this message, you don’t want your users to be confronted with a message you tell them to accept (otherwise it won’t work and they’re to blame).

In this article I’ll explain why this message is displayed and how you can prevent it.

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Receiver 11.05 for Windows CE fixes disappearing smartcard in Citrix session (UZI pas)

Author: Ingmar Verheij

UZI pas

Last year I wrote an article about a smartcard (UZI pas) that couldn’t be used from a Windows CE 6 thin client in a Citrix XenApp environment. The problem seemed to be solved with a private client and installing Hotfix Rollup Pack 6 on the server.

Months later, when the customer started testing again, we discovered a new issue: The smartcard reader device disappeared from the session!

It took 4 months and 5 Citrix support engineers (Ross, Shane, Romulo, Brian and finally Anthony) before we solved the issue with an updated Citrix Receiver for Windows CE 11.05 (I’ve provided the files below).

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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:

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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.

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Session freeze when starting Excel

Environment
Windows 2003 Enterprise (32 bit), Citrix XenApp 5, RES Workspace Manager 2011, McAfee VirusScan Enterprise 8.7.0i.

Problem
When a opening an Excel workbook from Sharepoint the whole session freezes.

I asked the user to open an Excel workbook from Sharepoint and I noticed the following popup:

Some files can harm your computer. If the file information looks suspicious or you do not fully trust the source, do not open the file | You are opening the following file: | File name: My Workbook.xls | From: Sharepoint

So my first thought was that the user somehow clicked this message to the background and IE was waiting for a response.

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Our partner Denamik has released Denamik LoadGen 2.3

Our partner Denamik has released a new version of Denamik LoadGen. The execution of massive load and stress tests is now easier than before. You can now record your own user action scripts from within LoadGen, and setup LoadBots to handle the execution of these scripts. LoadGen allows you to manage LoadBots to create remote sessions and evaluate your IT environment under stress. A built-in reporting facility will give you instant results.

What is new in LoadGen 2.3:

  • Rewrite of installation and activation of LoadBots
  • Rewrite of internal functions of the DUAF language to speed up interaction with XenApp desktops
  • Introducing the possibilities to add your own libraries to DUAF scripts

Feel free to check out Denamik LoadGen 2.3, it’s free up to 15 virtual users.