A few weeks ago, whenever I ran forge it didn't work. The minecraft launcher application disappears, then re opens with this error message:
2016-06-18 12:00:02,616 WARN Unable to instantiate org.fusesource.jansi.WindowsAnsiOutputStream
2016-06-18 12:00:02,617 WARN Unable to instantiate org.fusesource.jansi.WindowsAnsiOutputStream
[12:00:02] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker
[12:00:02] [main/INFO] [LaunchWrapper]: Using primary tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker
[12:00:02] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLTweaker
[12:00:02] [main/INFO] [FML]: Forge Mod Loader version 12.16.1.1887 for Minecraft 1.9 loading
[12:00:02] [main/INFO] [FML]: Java is Java HotSpot 64-Bit Server VM, version 1.8.0_25, running on Windows 8.1:amd64:6.3, installed at C:\Program Files (x86)\Minecraft\runtime\jre-x64\1.8.0_25
[12:00:02] [main/INFO] [FML]: Loading tweaker cpw.mods.fml.common.launcher.FMLTweaker from forge-1.7.10-10.13.4.1614-1.7.10-universal.jar
[12:00:02] [main/INFO] [FML]: Loading tweaker shadersmod.launch.SMCTweaker from ShadersMod-v2.4.12mc1.8.jar
[12:00:02] [main/ERROR] [FML]: The coremod TMIForgeLoader is requesting minecraft version 1.8 and minecraft is 1.9. It will be ignored.
[12:00:02] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLInjectionAndSortingTweaker
[12:00:02] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
[12:00:02] [main/ERROR] [LaunchWrapper]: Unable to launch
java.lang.RuntimeException: FML was unable to install the security manager. The game will not start
at cpw.mods.fml.common.launcher.FMLTweaker.<init>(FMLTweaker.java:39) ~[forge-1.7.10-10.13.4.1614-1.7.10-universal.jar:?]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[?:1.8.0_25]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[?:1.8.0_25]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[?:1.8.0_25]
at java.lang.reflect.Constructor.newInstance(Constructor.java:408) ~[?:1.8.0_25]
at java.lang.Class.newInstance(Class.java:438) ~[?:1.8.0_25]
at net.minecraft.launchwrapper.Launch.launch(Launch.java:98) [launchwrapper-1.12.jar:?]
at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrapper-1.12.jar:?]
Caused by: java.lang.SecurityException: Cannot replace the FML security manager
at net.minecraftforge.fml.relauncher.FMLSecurityManager.checkPermission(FMLSecurityManager.java:35) ~[forge-1.9-12.16.1.1887.jar:?]
at java.lang.System.setSecurityManager0(System.java:300) ~[?:1.8.0_25]
at java.lang.System.setSecurityManager(System.java:291) ~[?:1.8.0_25]
at cpw.mods.fml.common.launcher.FMLTweaker.<init>(FMLTweaker.java:35) ~[forge-1.7.10-10.13.4.1614-1.7.10-universal.jar:?]
... 7 more
Exception in thread "main" [12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: net.minecraftforge.fml.relauncher.FMLSecurityManager$ExitTrappedException
[12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: at net.minecraftforge.fml.relauncher.FMLSecurityManager.checkPermission(FMLSecurityManager.java:30)
[12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.lang.SecurityManager.checkExit(SecurityManager.java:761)
[12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.lang.Runtime.exit(Runtime.java:107)
[12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: at java.lang.System.exit(System.java:968)
[12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: at net.minecraft.launchwrapper.Launch.launch(Launch.java:138)
[12:00:02] [main/INFO] [sTDERR]: [java.lang.ThreadGroup:uncaughtException:1052]: at net.minecraft.launchwrapper.Launch.main(Launch.java:28)
Please help!