• 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 during running / active sessions does not work. The reader is visible, but cannot be used due to unknown reader status. Only relevant for CWA versions earlier than 2112.
  • There are known issues with GStreamer 1.0 in combination with Citrix. These occur with multimedia redirection of H.264, MPEG1, and MPEG2. (GStreamer 1.0 is used if browser content redirection is enabled active.)
  • Browser content redirection does not work with activated DRI3 and hardware-accelerated H.264 deep compression codec enabled.
  • Enabled DRI3 on an AMD GPU with enabled Citrix H.264 acceleration could lead to a 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.
  • Currently, H.264 for Citrix sessions cannot be used in parallel with video input acceleration.

OSC Installer

  • OSC not deployable with IGEL Deployment Appliance: New version 11.3 is required for deployment of IGEL OS 11.06. and later.


  • AVD MS-Teams optimization can crash the AVD client if H264 software decoder is used (fluh264dec). AVD prefers the hardware decoders (fluvadec) but when there are no hardware decoders or when all hardware decoders are in use already, the software decoder is utilized, which may randomly crash the AVD client. It is likely when it crashes in a certain MS-Teams call, it might crash quite soon again when rejoining the same call. A fix for that is under development.
    workaround is to disable incoming video in such MS-Teams calls, which is an option in the "..." menu from the control bar during an active call.
  • H264 hardware decoding for MS-Teams optimization is currently limited to non-AMD devices due to stability issues on AMD devices.

VMware Horizon

  • 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 is not possible.
  • The on-screen keyboard in Horizon appliance mode does not work correctly with the local logon.
    It is necessary to switch off local logon and enable the following two keys via IGEL registry:
  • Zoom VDI Media Plugin versions below 5.8.0 make Horizon Client crash upon connection to the remote desktop in cases when TC Setup is running at the same time.
  • With the usage of the PCoIP protocol, the virtual channel provided by VMware used for serial port and scanner redirection could freeze on logout from the remote session.
    This happens only with enabled scanner or serial port redirection. The freeze does not occur if both redirection methods are enabled or none of them. The Blast Protocol is not affected by this bug.
    The respective settings can be found in the IGEL Registry:
  • Keyboard Input Source Language Synchronization works only with usage of local layout and deadkeys enabled.
    If a keyboard layout is used which has deadkeys disabled (which is the default on IGEL OS), Horizon client falls back to en-US layout.
  • PCoIP sessions may crash in some cases, switching to Blast Protocol is recommended then. H.264/HEVC encoding can be disabled when overall performance is too low.
  • Client drive mapping and USB redirection for storage devices can be enabled at the same time, but this could lead to sporadical problems.
    Horizon Client tracks the drives which are dynamically mounted and adds them to the remote session using client drive mapping, means USB redirection is not used for these devices then.
    However, in case of devices like USB SD card readers, Horizon does not map them as client drives but forcefully uses USB redirection which results in an unclean unmount.
    As a workaround, the IDs of these card readers can be added to IGEL USB access rules and denied.

Parallels Client

  • Attached storage devices appear as network drives in the remote session.
  • USB device redirection is considered experimental for the Parallels client for Linux.


  • With enabled Citrix Browser Content Redirection (BCR), Firefox has no H.264 and AAC multimedia codec support. This means when codec support is needed in Firefox, BCR needs to be disabled. Citrix Browser Content Redirection is disabled by default.


  • Wakeup from system suspend fails on DELL Latitude 5510.
  • If applications are configured to start after established network connection and network mounts are configured, spurious "Failed to start application" notifications may be shown. The applications still start.


  • 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 2010 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 triggered / necessary).
  • Glibc has a serious memcpy performance regression on AMD Zen-based systems.


  • The right screen when using a multiscreen environment may not be shown correctly.
    Workaround: The horizontal offset should be set to the width of the monitor (e.g. if the monitor has a width of 1920, the offset should be set to 1920).

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.
  • Browser Appliance mode can fail when the Web URL contains special control characters like ampersands (& character).
    Workaround: Add quotes at the beginning and the end of an affected URL. Example: ''


  • 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 Advantech POC-W243L does not work. Therefore, sound output goes through a possibly connected headset and also the internal speakers.
  • UD3 M340C: Sound preferences are showing Headphone & Microphone, although not connected.


  • 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.