Wouter

That did the trick. Thanks!

The big error is: [1019/123010:INFO:ClientHandler.cpp(155)] Hiding launcher! [1019/123010:WARNING:x11_util.cc(1404)] X error received: serial 174, error_code 3 (BadWindow (invalid Window parameter)), request_code 4, minor_code 0 (X_DestroyWindow) [1019/123010:INFO:GameCallbacks.cpp(199)] game/game () info Exception in thread "main" java.lang.ClassCastException: java.base/jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to java.base/java.net.URLClassLoader [1019/123010:INFO:GameCallbacks.cpp(199)] game/game () info at net.minecraft.launchwrapper.Launch.<init>(Launch.java:34) [1019/123010:INFO:GameCallbacks.cpp(199)] game/game () info at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [1019/123010:INFO:GameCallbacks.cpp(199)] launcher/monitor (Process Monitor) fatal Process crashed with exit code 1

Hello, I just tried running minecraft on my Linux machine. It runs Kubutu 19.04.1 LTS. Normal minecraft launches just fine. But when I install forge the game does not launch. The only log I can get is my launcher_log.txt. I can see some errors about GLXBadWindow. I dont get these when I launch normal minecraft (1.12). Does anyone know a fix? Greetings, Wouter Versions: Forge: forge-1.12.2-14.23.5.2768 Linux: Kubuntu 19.04.1 LTS System: I7-7700HQ GTX 1050ti (using Nvidia-396) Session: X DisplayManager: KDE Plasma Status: Up to date. launcher_log.txt