Tempak

I'm sure that he faced same issue, but quoted only part of the log. It's because I used non vanilla 3rd party launcher, which does not include all required dependecies in class path. There is no issue using latest genuine vanilla launcher. So my workaround may help for someone who is trying to use different or maybe outdated launcher. I just compared command line from my launcher and vanilla one, and I found that indeed part of libraries are not listed in classpath, not only mergetool. In my case following are missing: libraries\net\minecraftforge\mergetool\1.1.5\mergetool-1.1.5-api.jar libraries\com\mojang\patchy\2.2.10\patchy-2.2.10.jar libraries\org\lwjgl\lwjgl-glfw\3.3.1\lwjgl-glfw-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl-glfw\3.3.1\lwjgl-glfw-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl-glfw\3.3.1\lwjgl-glfw-3.3.1-natives-windows-x86.jar libraries\org\lwjgl\lwjgl-jemalloc\3.3.1\lwjgl-jemalloc-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl-jemalloc\3.3.1\lwjgl-jemalloc-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl-jemalloc\3.3.1\lwjgl-jemalloc-3.3.1-natives-windows-x86.jar libraries\org\lwjgl\lwjgl-openal\3.3.1\lwjgl-openal-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl-openal\3.3.1\lwjgl-openal-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl-openal\3.3.1\lwjgl-openal-3.3.1-natives-windows-x86.jar libraries\org\lwjgl\lwjgl-opengl\3.3.1\lwjgl-opengl-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl-opengl\3.3.1\lwjgl-opengl-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl-opengl\3.3.1\lwjgl-opengl-3.3.1-natives-windows-x86.jar libraries\org\lwjgl\lwjgl-stb\3.3.1\lwjgl-stb-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl-stb\3.3.1\lwjgl-stb-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl-stb\3.3.1\lwjgl-stb-3.3.1-natives-windows-x86.jar libraries\org\lwjgl\lwjgl-tinyfd\3.3.1\lwjgl-tinyfd-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl-tinyfd\3.3.1\lwjgl-tinyfd-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl-tinyfd\3.3.1\lwjgl-tinyfd-3.3.1-natives-windows-x86.jar libraries\org\lwjgl\lwjgl\3.3.1\lwjgl-3.3.1-natives-windows.jar libraries\org\lwjgl\lwjgl\3.3.1\lwjgl-3.3.1-natives-windows-arm64.jar libraries\org\lwjgl\lwjgl\3.3.1\lwjgl-3.3.1-natives-windows-x86.jar So this issue is not related to vanilla launcher at all, it's not Forge installer fault. It's 3rd party launcher failure, which can be workarounded by adding missing dependencies to class path manually if someone really want to stick with non-vanilla launcher.

Same issue with Forge for 1.20 and 1.20.1. It works fine for 1.19.4, and older. I did install forge-1.20.1-47.0.35-installer.jar, and got following exception while running game using 1.20.1-forge-47.0.35 profile: [00:32:18] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher running: args [--username, xxx, --version, 1.20.1-forge-47.0.35, --gameDir, C:\Users\xxx\AppData\Roaming\.minecraft, --assetsDir, C:\Users\xxx\AppData\Roaming\.minecraft\assets, --assetIndex, 5, --uuid, 11111111111111111111111111111111, --accessToken, ????????, --clientId, ${clientid}, --xuid, ${auth_xuid}, --userType, legacy, --versionType, release, --launchTarget, forgeclient, --fml.forgeVersion, 47.0.35, --fml.mcVersion, 1.20.1, --fml.forgeGroup, net.minecraftforge, --fml.mcpVersion, 20230612.114412] [00:32:18] [main/INFO] [cp.mo.mo.Launcher/MODLAUNCHER]: ModLauncher 10.0.9+10.0.9+main.dcd20f30 starting: java version 17.0.7 by Eclipse Adoptium; OS Windows 10 arch amd64 version 10.0 [00:32:18] [main/FATAL] [cp.mo.mo.LaunchPluginHandler/MODLAUNCHER]: Encountered serious error loading launch plugin service. Things will not work well java.util.ServiceConfigurationError: cpw.mods.modlauncher.serviceapi.ILaunchPluginService: Provider net.minecraftforge.fml.loading.RuntimeDistCleaner could not be instantiated at java.util.ServiceLoader.fail(ServiceLoader.java:586) ~[?:?] {} at java.util.ServiceLoader$ProviderImpl.newInstance(ServiceLoader.java:813) ~[?:?] {} at java.util.ServiceLoader$ProviderImpl.get(ServiceLoader.java:729) ~[?:?] {} at cpw.mods.modlauncher.util.ServiceLoaderUtils.lambda$streamWithErrorHandling$0(ServiceLoaderUtils.java:39) ~[modlauncher-10.0.9.jar:?] {} at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197) ~[?:?] {} at java.util.ServiceLoader$ProviderSpliterator.tryAdvance(ServiceLoader.java:1499) ~[?:?] {} at java.util.Spliterator.forEachRemaining(Spliterator.java:332) ~[?:?] {} at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509) ~[?:?] {} at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499) ~[?:?] {} at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921) ~[?:?] {} at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) ~[?:?] {} at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682) ~[?:?] {} at cpw.mods.modlauncher.LaunchPluginHandler.<init>(LaunchPluginHandler.java:46) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.Launcher.<init>(Launcher.java:65) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.Launcher.main(Launcher.java:78) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:141) ~[bootstraplauncher-1.1.2.jar:?] {} Caused by: java.lang.NoClassDefFoundError: net/minecraftforge/api/distmarker/OnlyIn at net.minecraftforge.fml.loading.RuntimeDistCleaner.<clinit>(RuntimeDistCleaner.java:42) ~[fmlloader-1.20.1-47.0.35.jar%2380!/:1.0] {} at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?] {} at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77) ~[?:?] {} at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?] {} at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499) ~[?:?] {} at java.lang.reflect.Constructor.newInstance(Constructor.java:480) ~[?:?] {} at java.util.ServiceLoader$ProviderImpl.newInstance(ServiceLoader.java:789) ~[?:?] {} ... 16 more Caused by: java.lang.ClassNotFoundException: net.minecraftforge.api.distmarker.OnlyIn at jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) ~[?:?] {} at java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[?:?] {} at cpw.mods.cl.ModuleClassLoader.loadClass(ModuleClassLoader.java:137) ~[securejarhandler-2.1.10.jar:?] {} at java.lang.ClassLoader.loadClass(ClassLoader.java:520) ~[?:?] {} at net.minecraftforge.fml.loading.RuntimeDistCleaner.<clinit>(RuntimeDistCleaner.java:42) ~[fmlloader-1.20.1-47.0.35.jar%2380!/:1.0] {} at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:?] {} at jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:77) ~[?:?] {} at jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:?] {} at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499) ~[?:?] {} at java.lang.reflect.Constructor.newInstance(Constructor.java:480) ~[?:?] {} at java.util.ServiceLoader$ProviderImpl.newInstance(ServiceLoader.java:789) ~[?:?] {} ... 16 more [00:32:18] [main/INFO] [ne.mi.fm.lo.ImmediateWindowHandler/]: Loading ImmediateWindowProvider fmlearlywindow [00:32:19] [main/INFO] [EARLYDISPLAY/]: Trying GL version 4.6 [00:32:19] [main/INFO] [EARLYDISPLAY/]: Requested GL version 4.6 got version 4.6 [00:32:19] [main/ERROR] [ne.mi.fm.lo.FMLLoader/CORE]: Dist Cleaner is missing, we need this to run [00:32:19] [main/ERROR] [cp.mo.mo.TransformationServiceDecorator/MODLAUNCHER]: Service failed to load fml cpw.mods.modlauncher.api.IncompatibleEnvironmentException: Missing DistCleaner, cannot run! at net.minecraftforge.fml.loading.FMLLoader.lambda$onInitialLoad$2(FMLLoader.java:94) ~[fmlloader-1.20.1-47.0.35.jar:1.0] {} at java.util.Optional.orElseThrow(Optional.java:403) ~[?:?] {} at net.minecraftforge.fml.loading.FMLLoader.onInitialLoad(FMLLoader.java:92) ~[fmlloader-1.20.1-47.0.35.jar:1.0] {} at net.minecraftforge.fml.loading.FMLServiceProvider.onLoad(FMLServiceProvider.java:100) ~[fmlloader-1.20.1-47.0.35.jar:1.0] {} at cpw.mods.modlauncher.TransformationServiceDecorator.onLoad(TransformationServiceDecorator.java:53) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.TransformationServicesHandler.lambda$loadTransformationServices$11(TransformationServicesHandler.java:116) ~[modlauncher-10.0.9.jar:?] {} at java.util.HashMap$Values.forEach(HashMap.java:1065) ~[?:?] {} at cpw.mods.modlauncher.TransformationServicesHandler.loadTransformationServices(TransformationServicesHandler.java:116) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.TransformationServicesHandler.initializeTransformationServices(TransformationServicesHandler.java:48) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.Launcher.run(Launcher.java:88) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.Launcher.main(Launcher.java:78) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) ~[modlauncher-10.0.9.jar:?] {} at cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:141) ~[bootstraplauncher-1.1.2.jar:?] {} [00:32:19] [main/ERROR] [cp.mo.mo.TransformationServicesHandler/MODLAUNCHER]: Found 1 services that failed to load : [fml] Exception in thread "main" cpw.mods.modlauncher.InvalidLauncherSetupException: Invalid Services found fml at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.TransformationServicesHandler.validateTransformationServices(TransformationServicesHandler.java:110) at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.TransformationServicesHandler.initializeTransformationServices(TransformationServicesHandler.java:49) at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.Launcher.run(Launcher.java:88) at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.Launcher.main(Launcher.java:78) at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:26) at MC-BOOTSTRAP/[email protected]/cpw.mods.modlauncher.BootstrapLaunchConsumer.accept(BootstrapLaunchConsumer.java:23) at [email protected]/cpw.mods.bootstraplauncher.BootstrapLauncher.main(BootstrapLauncher.java:141) I found that missing class file "java.lang.NoClassDefFoundError: net/minecraftforge/api/distmarker/OnlyIn" is now included in mergetool-x.x.x-api.jar instead of forgespi-x.x.x.jar for 1.19.x. What I did was locate merge tool version used by forge looking into Forge profile config file: %APPDATA%\.minecraft\versions\1.20.1-forge-47.0.35\1.20.1-forge-47.0.35.json and searching for "mergetool" string, then it's path attribute: "path": "net/minecraftforge/mergetool/1.1.5/mergetool-1.1.5-api.jar" Then I added this to java modules path within same 1.20.1-forge-47.0.35.json file, within "jvm" as first module next to "-p" parameter: Before change: "-p", "${library_directory}/cpw/mods/bootstraplauncher/1.1.2/bootstraplauncher-1.1.2.jar${classpath_separator}..... After change: "-p", "${library_directory}/net/minecraftforge/mergetool/1.1.5/mergetool-1.1.5-api.jar${classpath_separator}${library_directory}/cpw/mods/bootstraplauncher/1.1.2/bootstraplauncher-1.1.2.jar${classpath_separator}..... It works, but I don't know why this library is not included into forge json config file by Forge installer by default. Maybe some launchers are including all libraries from %APPDATA%\.minecraft\libraries\ into classpath, but others not.