Startup Issue with Minecraft - Wont start up at all

Technical Support
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1

System Information

Field Value
Operating System Linux - Debian GNU/Linux 12 on x86_64
Product AMP ‘Phobos’ v2.6.4.2 (Mainline)
Virtualization Docker
Application Minecraft
Module MinecraftModule
Running in Container Yes
Current State Failed

Problem Description

Issue

Wont start up now that it is on ftb ultimate reloaded even after update

Reproduction Steps

  • switched to ftb ultimate
  • that was the only thing that changed
  • still the only thing
2

What does the console show? Did you follow the guide for using modpacks with AMP?

3

Caused by: java.lang.ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader (jdk.internal.loader.ClassLoaders$AppClassLoader and java.net.URLClassLoader are in module java.base of loader ‘bootstrap’)

I dont know what any of this means i just play minecraft

4

Make sure you have the correct Java Version selected for the version of MC FTB Ultimate uses.
See this guide here for more info (specifically section 2 onward)