Powerfuse not launching on XenApp 5.0

Friday, October 3, 2008
By Edwin

We installed a XenApp 5.0 test environment on Windows 2008 server 32 bit. We also installed RES Powerfuse and we publish the pwrstart.exe for users.
Every time when we launch the pwrstart.exe from the program neighboorhood the ica session starts but it only opens a Windows Desktop and not a Powerfuse desktop.As we check the eventlogs we see no errors at all also XenApp 5.0 is not presenting any erros so ever.
Does anyone have an idea how to resolve this problem?

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3 Responses to “Powerfuse not launching on XenApp 5.0”

  1. Ruben Spruijt

    When logging on to RES PowerFuse, only Explorer will be opened instead of full Windows desktop

    When logging on to RES PowerFuse, only an Explorer will be opened instead of a full Windows desktop with a taskbar and desktop icons.

    Cause 1

    Citrix Presentation Server version 4 has a new feature that actively monitors whether the explorer.exe is started in a published application and prevents this explorer.exe from running in shell mode.

    This is a Citrix security feature that prevents a user from launching the explorer.exe in shell mode in a published application. If an explorer.exe file is triggered by the user, it is started in file browser mode instead.

    Normally, the first instance of explorer.exe will always be an explorer.exe in shell mode (Windows Desktop) and the second instance of explorer.exe will always be an explorer.exe in file explorer mode.

    Solution 1

    95% probability

    The behavior described in the cause is not desirable when using RES PowerFuse in combination with the Windows Desktop shell.

    After the Citrix-published application RES PowerFuse (pwrstart.exe) is started, the explorer.exe shell (Windows Shell) will be started, to give the user access to a managed and secure Windows Desktop. Therefore, the Citrix hook on the explorer.exe file should be disabled.

    To disable the hook on the explorer.exe file, browse to the following registry key and change the value data to “0″ on all Citrix servers:

    [32bit Windows]
    System Key: [HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\CtxHook\AppInit_DLLs\Seamless Explorer]
    Value Name: Flag
    Data Type: REG_DWORD (DWORD Value)
    Value Data: 6 = enable Explorer hook (default), 0 = Disable Explorer hook

    [64bit Windows]
    System Key: [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Citrix\CtxHook64\AppInit_DLLs\Seamless Explorer]
    Value Name: Flag
    Data Type: REG_DWORD (DWORD Value)
    Value Data: 6 = enable Explorer hook (default), 0 = Disable Explorer hook

    IMPORTANT NOTE: RES PowerFuse SR2 and earlier will always start the 32bits explorer.exe and therefore the 32bit Windows Citrix Hook should be disabled!

    Changing this registry key prevents the C:\Program Files\Citrix\system32\explhook.dll from being started. This DLL sets the specific hook on the explorer.exe file.

    This step should be performed on all Terminal Servers where Citrix Presentation Server 4 is installed and where RES PowerFuse is used in combination with the Windows shell instead of the RES PowerFuse shell.

    The problem can also occur after updating Citrix Presentation server 4 with Citrix update patches.

    This article is also published in the Citrix Knowledge Base under article number CTX106767: http://support.citrix.com/kb/entry!default.jspa?categoryID=710&externalID=CTX106767

    Cause 2

    RES does not support to start RES PowerFuse on a Terminal Server by changing the system default shell.
    [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]

    Solution 1

    95% probability

    To start RES PowerFuse, start “Terminal Services Configuration” and specify “%Program Files%\RES PowerFuse\pwrstart.exe” as initial application on the “Environment” tab of the desired protocol.

  2. Hi Ruben,

    Thx for your reply

    Yes we know this was a known issue in CPS 3.0 and 4.0 and we already disabled the CtxHook key.This was without any result.So we guess it has nothing to dot with it.
    You often see this problem occur after installing new Microsoft versions and patches and after installing XenApp patches and hotfix rollup packs.
    So this is RES Powerfuse 2008 SR2 on Windows 2008 32 bit Terminal server with the new XenApp 5.0 a lot of new stuff so to say.
    I can’t imagine that this wasn’t tested by someone else before.Gonna use filemon en regmon to find out if there are any denied folders and regsitry keys. So we still got the same problem.

    Just one other strange thing.

    If we launch the published RES Powerfuse application a Micorsoft server 2008 desktops opens up you can logon and you get a published desktop nothing else happens. If we in that opened desktop click on the RES Powerfuse icon it works flawless. So somehow Windows or XenApp doesn’t understand how to start de RES Powerfuse desktop.

    I guess we gonna test the new SR3 release next week thats XenApp 5.0 supported by RES.

  3. priyanka

    Hi Edwin,

    I am facing the same problem , I have published an application on citrix which launches explorer.Application runs fine when I run it directly by clicking exe but when published its not getting the shellwindows. I tried disabling the CtxHook also but no success.
    Please share if you have got the solution of this prob;em.
    Waiting for ur reply.


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