Unable to open display, with GTK_BACKEND=X11

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1

Hello,

I’m running Fedora 43 with KDE (non-atomic version) and want to use a software called KNIME, which offers a Linux package available for download on their official website (it’s not in the Fedora repositories).

When I launch the application, a message appears stating that Wayland is not yet fully supported. The developers suggest running KNIME with the following command:
GTK_BACKEND=X11 ./knime

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However, when I execute this command, I encounter an error and I wondering if I have everything to force an execution in X11

I’m a relatively new Linux user, but I’ve gathered that Wayland is a modern replacement for X11, and there are still compatibility layers to bridge the two (I assume this is why I see a “Wayland to X11 video bridge” in my notification bar).
Perhaps I’m missing some components required to run this application properly?

Knime: Unable to open display: (a translation of French)
Knime: Unable to open display:
Knime: Unable to open display:
Knime:
An error has occurred. See the log file
/home/zarkoff/Knime/configuration/1772023882611.log

Do you have any idea what might be causing this or how to resolve it?

log file,

!SESSION 2026-02-25 13:51:22.542 -----------------------------------------------
eclipse.buildId=unknown
java.version=21.0.9
java.vendor=Eclipse Adoptium
BootLoader constants: OS=linux, ARCH=x86_64, WS=gtk, NL=fr_FR
Command-line arguments:  -os linux -ws gtk -arch x86_64

!ENTRY org.eclipse.osgi 4 0 2026-02-25 13:51:23.240
!MESSAGE Application error
!STACK 1
org.eclipse.swt.SWTError: No more handles [gtk_init_check() failed]
	at org.eclipse.swt.SWT.error(SWT.java:4975)
	at org.eclipse.swt.widgets.Display.createDisplay(Display.java:1203)
	at org.eclipse.swt.widgets.Display.create(Display.java:1127)
	at org.eclipse.swt.graphics.Device.<init>(Device.java:188)
	at org.eclipse.swt.widgets.Display.<init>(Display.java:633)
	at org.eclipse.swt.widgets.Display.<init>(Display.java:624)
	at org.eclipse.ui.internal.Workbench.createDisplay(Workbench.java:789)
	at org.eclipse.ui.PlatformUI.createDisplay(PlatformUI.java:185)
	at org.knime.product.rcp.KNIMEApplication.createDisplay(KNIMEApplication.java:370)
	at org.knime.product.rcp.KNIMEApplication.start(KNIMEApplication.java:144)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:219)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:149)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:115)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:467)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:298)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:627)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:575)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1431)
	at org.eclipse.equinox.launcher.Main.main(Main.java:1403)

Thank you

3

Not sure if this will fix it, but the command they suggest is:

GDK_BACKEND=x11 ./knime

What if you try that exact command? The one you ran has “GTK” instead of “GDK”, and uppercase “X11” instead of lowercase “x11”.

4

The command is correct, the error seems to indicate that your terminal doesn’t have DISPLAY variable set. Do you see it in the output of env?

5

Oh, of course—it was “x11” not “X11”… and I also typed GTK instead of GDK? I need new glasses ASAP.
GDK_BACKEND=x11 ./knime works…

Sorry and thank you !

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