Cannot start UE4 in Ubuntu 20.04 due to SDL X11 error/warning

Hello Community,

I am really new to Linux and Unreal Engine but I thought it is never to late… Ubuntu 20.04 is running in WSL2 on Windows 10.

I have followed the documention (Linux Quick Start | Unreal Engine Documentation) and got the the last step! Unfortunetly, I do get this message:



[2021.03.12-06.46.34:704] 0]LogInit: Warning: Could not initialize SDL: X11 not available
[2021.03.12-06.46.34:704] 0]LogInit: - Physical RAM available (not considering process quota): 25 GB (25594 MB, 26208420 KB, 26837422080 bytes)
[2021.03.12-06.46.34:704] 0]LogInit: - VirtualMemoryAllocator pools will grow at scale 1.4
[2021.03.12-06.46.34:704] 0]LogInit: - MemoryRangeDecommit() will be a no-op (re-run with -vmapoolevict to change)
[2021.03.12-06.46.34:728] 0]LogInit: Physics initialised using underlying interface: PhysX
[2021.03.12-06.46.34:748] 0]LogInit: Using OS detected language (en-US-POSIX).
[2021.03.12-06.46.34:748] 0]LogInit: Using OS detected locale (en-US-POSIX).
[2021.03.12-06.46.34:749] 0]LogTextLocalizationManager: No specific localization for 'en-US-POSIX' exists, so the 'en' localization will be used.
[2021.03.12-06.46.34:898] 0]LogInit: Initializing SDL.
[2021.03.12-06.46.34:902] 0]LogInit: Warning: Could not initialize SDL: X11 not available
[2021.03.12-06.46.34:902] 0]LogInit: Warning: FLinuxSplashState::InitSplashResources() : InitSDL() failed, there will be no splash.
[2021.03.12-06.46.34:902] 0]LogInit: Initializing SDL.
[2021.03.12-06.46.34:906] 0]LogInit: Warning: Could not initialize SDL: X11 not available
[2021.03.12-06.46.34:906] 0]LogInit: Error: FLinuxApplication::CreateLinuxApplication() : InitSDL() failed, cannot create application instance.
[2021.03.12-06.46.34:906] 0]LogCore: FUnixPlatformMisc::RequestExit(bForce=true, ReturnCode=1)
[2021.03.12-06.46.34:906] 0]LogCore: FUnixPlatformMisc::RequestExit(1)


I did install the latest release of lib sdl with


sudo apt-get install -y libsdl2-2.0-0

But it did not work… What do I do wrong??

Many thanks in advance!

1 Like

Did u found any solution for this error?

OP was using the gnome or another desktop env with wayland. On gnome it can be fixed by login in with classic mode. On kde with x11. Also should use proprietary drivers.

yep, you should be running X not Wayland, probably. Or figure out how to run X clients on top of Wayland.

1 Like

WSL2 should be console only unless you are on windows previews (which use a Wayland Server) or using GWSL which uses X11.

You can try to set SDL_VIDEODRIVER=wayland before running UE4 to see if you can run it with wayland.