Virtual Lab Error – Application window does not appear on screen

Problem 
After opening an application on Virtual Lab from Windows, the program appears to be running in the taskbar, but never displays to the screen and allows user to interact with it.
Solutions 
This appears to be caused by a combination of Windows Creator Update and Citrix Receiver version installed on the machine.  We have been able to successfully resolve the issue by Adding a new Registry Key to disable Hardware Acceleration or by installing an older version of the Citrix receiver.

-Adding a Registry Key to Disable Hardware Acceleration in the Citrix Receiver

WARNING Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system.

To resolve the issue we need to create the following registry in Windows.

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\ICA Client\Graphics Engine] “HWacceleration”=dword:00000000

To do this use the search bar in Windows to search “regedit”, you should see the registry editor as a result.
screenshot
 

Open that and you should have a window similar to the one shown below.

screenshot
 

In the Registry Editor, expand the HKEY_LOCAL_MACHINE folder > SOFTWARE > POLICIES.  At this point we will need to create the additional folders.  Right click on POLICIES > new > key > name the new key “Citrix” > right click on the newly created Citrix folder > choose new > key > Name the new key “ICA Client” > right click on the newly created ICA Client folder > choose new > key > name the new key “Graphics Engine”.

Now we need to add a value in the newly created Graphics Engine key.  Select Graphics Engine, then in the pane to the right, right click on “type” > choose new >  DWORD (32-bit) Value > that will create a new entry > name it “HWacceleration”.   (don’t type out the quotation marks).  You should then have a window that looks like the one shown below.

screenshot

 

Close the registry editor and then launch your desired application in Virtual Lab.  The application should open normally now.

-Uninstall the current version of Citrix Receiver and then install version 4.6 

Another option is uninstalling the installed version of the Citrix Receiver (go to Control Panel->Programs and Features->Select Citrix Receiver->Select Uninstall) and  then download/install Citrix Receiver 4.6 (please note this is an older version).
After installing this version, you should be able to launch your application again and it open normally.