ToxicDart

I am having the same problem. Everything was working fine until this morning with the 1.8 pre release. That's the only thing I know of that changed. I removed and reinstalled all my forge and minecraft in an attempt to fix it and nothing changed. I was running galacticraft before this, and I ensured that it was not galacticraft by simply removing all the mod jar files from my mods folder. Here is my crash log: [11:42:47] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker [11:42:47] [main/INFO] [LaunchWrapper]: Using primary tweak class name cpw.mods.fml.common.launcher.FMLTweaker [11:42:47] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLTweaker [11:42:47] [main/INFO] [FML]: Forge Mod Loader version 7.10.25.1208 for Minecraft 1.7.10 loading [11:42:47] [main/INFO] [FML]: Java is Java HotSpot 64-Bit Server VM, version 1.8.0_20, running on Windows 7:amd64:6.1, installed at C:\Program Files\Java\jre1.8.0_20 [11:42:47] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker [11:42:47] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLDeobfTweaker [11:42:47] [main/INFO] [LaunchWrapper]: Calling tweak class cpw.mods.fml.common.launcher.FMLInjectionAndSortingTweaker [11:42:47] [main/ERROR] [LaunchWrapper]: Unable to launch java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(Unknown Source) ~[?:1.8.0_20] at java.util.ArrayList$Itr.remove(Unknown Source) ~[?:1.8.0_20] at net.minecraft.launchwrapper.Launch.launch(Launch.java:117) [launchwrapper-1.9.jar:?] at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.9.jar:?] Java HotSpot 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release