Citrix “Cannot start app. Please contact your help desk.”

After standing up a new Citrix site from scratch, we found Citrix Receiver/Workspace apps configured on client workstations configured with SSO couldn’t launch applications.

After a few hours of checking event logs and enabling every Receiver/Workspace logging feature, I only found very generic errors. The most “relevant” error found in the Receiver/Workspace app log was:

Monday, January 13, 2020/4:24:30 PM ICA launch failed from delivery service at https://storefront.url/Citrix/Store/resources/v2/WERbunchofjunkBJQdfdBf4tUHdbWUgSGdbHRoIE1h/launch/ica; reason: GeneralAppLaunchError
Monday, January 13, 2020/4:24:30 PM Got Comms Error
Monday, January 13, 2020/4:24:30 PM Request failed: General error

Searching this error lead me to

The Citrix article explains how to prepare a site for Pass-Through Authentication. Surprisingly, this parameter could be modified via the GUI in XenApp 6.5, but not newer.

Step two provides a PowerShell command which you can run on a site Delivery Controller:

asnp Citrix*
Set-BrokerSite -TrustRequestsSentToTheXmlServicePort $True

To validate the parameter took, run:


Validate TrustRequestsSentToTheXmlServicePort is set to True, then refresh Receiver/Workspace app and relaunch your application.


Citrix USB Error “Device appears to be in use and cannot be attached”

Device appears to be in use and cannot be attached. Do you want to force close the deivce and redirect.

If you’re attempting to redirect a USB device to Citrix and receive the error “Device appears to be in use and cannot be attached,” here’s how to suppress it. As the error indicates, the USB device that you’re attempting to redirect is in use on your local system and Receiver cannot redirect it without forcefully doing so. Depending on your particular scenario, this may or may not be a good idea. If you definitely want suppress this error, set the following Registry entry:

64 Bit:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Policies\Citrix\ICA Client\GenericUSB]
  • [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Citrix\ICA Client\GenericUSB]

32 Bit:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\ICA Client\GenericUSB]

Citrix Philips SpeechMike III USB Redirection

Philips SpeechMike III

Tested on model LFH3500 with MModal. If the device isn’t passed through to the VDA as a Generic USB device, the buttons on the microphone will not function.

Citrix Policy

Apply these Citrix policies to the VDA:

  • Client USB device redirection = Allowed
  • Client USB device redirection rules = Allow: VID=0911 PID=0C1C #Philips SpeechMike III
  • Client USB device optimization rules = Mode=00000001 VID=0911 PID=0C1C #Philips SpeechMike III
    • Mode=00000001 disables optimization

Group Policy

Apply these group policy settings to the connecting client workstation:

  • Computer Configuration/Policies/Administrative Templates/Citrix Components/Citrix Receiver/Remoting client devices/Generic USB Remoting
    • Existing USB Devices
      • Enabled
      • When desktop starts = Connect all available USB devices
    • New USB Devices
      • Enabled
      • When a USB device is inserted = Connect the USB Device
    • USB Device Rules
      • Enabled
      • USB Device Rules = Allow: VID=0911 PID=0C1C #Philips SpeechMike III;

Client Registry

Apply these registry entries to the connecting client workstation:

  • [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Policies\Citrix\ICA Client\GenericUSB]

    • Necessary if the device could be potentially in use prior to connecting to the VDA, otherwise a warning will appear to the user
  • [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Policies\Citrix\ICA Client\GenericUSB\Devices\VID0911 PID0C1C]

    • Disabled optimization on the client