• To launch multiple desktop sessions with Citrix HDX RTME and Citrix H.264 acceleration plugin, the following registry key must be enabled. 

    ParameterActivate workaround for dual RTME sessions and H264 acceleration
    Valueenabled / disabled
  • This workaround is not applicable when Enable Secure ICA is active for the specific delivery group.
  • Adding smartcard readers while the session is ongoing does not work. The reader is visible, but cannot be used due to permanently unknown reader status.
  • Citrix has known issues with GStreamer1.0 which describe problems with multimedia redirection of H.264, MPEG1, and MPEG2. GStreamer1.0 is used if browser content redirection is active.
  • Browser content redirection does not work with activated DRI3 and hardware-accelerated H.264 deep compression codec.
  • With activated DRI3 and an AMD GPU, Citrix H.264 acceleration plugin could freeze. Selective H.264 mode (API v2) is not affected by this issue.
  • Citrix H.264 acceleration plugin does not work with enabled server policy Optimize for 3D graphics workload in combination with server policy Use video codec compression > For the entire screen.

VMware Horizon

  • Client drive mapping and USB redirection for storage devices should not be enabled both at the same time.
    • On the one hand, when using USB redirection for storage devices:
      The USB on-insertion feature is only working when the client drive mapping is switched off. In the IGEL Setup client drive mapping can be found in:
      Sessions > Horizon Client > Horizon Client Global > Drive Mapping > Enable Drive Mapping.
      It is also recommended to disable local Storage Hotplug on setup page Devices > Storage Devices > Storage Hotplug.
    • On the other hand, when using drive mapping instead, it is recommended to either switch off USB redirection entirely or at least deny storage devices by adding a filter to the USB class rules.
      Furthermore, Horizon Client relies on the OS to mount the storage devices themselves. Enable local `Storage Hotplug` on setup page Devices > Storage Devices > Storage Hotplug.
  • External drives mounted already before connection do not appear in the remote desktop.
    Workaround: map the directory /media as a drive. Then the external devices will show up inside the media drive.
  • After disconnect of an RDP-based session, the Horizon main window which contains the server or sessions overview, cannot be resized anymore.
  • Copying Text from Horizon Blast sessions isn't possible.
  • The on-screen keyboard in Horizon appliance mode does not work correctly with the local logon.
    You have to switch off the local logon and switch on these two keys in the IGEL registry:
  • Zoom VDI Media Plugin makes Horizon Client crash upon connection to the remote desktop in cases when TCSetup is running at the same time.
  • When using the PCoIP protocol the virtual channel provided by VMware used for serial port and scanner redirection can make Horizon client hang on logout from the remote session.
    This happens if you enable only one of scanner or serial port redirection. The freeze does not occur if both redirection methods are enabled or none of them. The Blast Protocol isn't affected by this bug.
    The respective settings can be found here in the IGEL Registry:

Parallels Client

  • Native USB redirection does not work with Parallels Client.


  • H.264 decoding is not supported anymore.


  • TP-Link Archer T2UH WiFi adapters do not work after system suspend/resume.
    Workaround: Disable system suspend at IGEL Setup > System > Power Options > Shutdown.

Cisco JVDI Client

  • There may be a segfault shown in the logs (during log out of Citrix Desktop session). Occurs only when using Citrix Workspace app 20.10 and Cisco JVDI.

Base system

  • Hyper-V (Generation 2) needs a lot of memory (RAM). The machine needs a sufficient amount of memory allocated.
  • Update from memory stick requires network online state (at least when multiple update stages are involved)
  • Unreliable messages in user dialog for applying settings during boot. Could occur when new settings were fetched from the UMS.


  • Some stability issues may remain.

Firmware update

Appliance Mode

  • When ending a Citrix session in browser appliance mode, the browser is restarted twice instead of once.
  • Appliance mode RHEV/Spice: spice-xpi firefox plugin is no longer supported.
    The Console Invocation has to allow Native client (auto is also possible) and should be started in fullscreen to prevent any opening windows.


  • The current VirtualBox Guest Tools/Drivers will not work with VirtualBox 5.2.x or older hosts. This results in a black screen and non-working graphic. 
    Possible workaround: Installation with Failsafe Installation + Recovery and set of x.drivers.force_vesa registry key to "true".


  • IGEL UD2 (D220) fails to restore the volume level of the speaker when the device used firmware version 11.01.110 before.
  • Audio jack detection on Advantec POC-W243L does not work. Therefore, sound output goes through a possibly connected headset and also the internal speakers.


  • Multimedia redirection with GStreamer could fail with the Nouveau GPU driver.


  • Some newer Delock 62599 active DisplayPort to DVI (4k) adapters only work on INTEL-based devices.

Remote Management

  • AIT feature with IGEL Starter License is only supported by UMS version 6.05.100 or newer.