FML was unable to install the security manager

[MrJeeves]

Every time I start my modded server (since I've upgraded to Forge 10.13.0.1208), I've been experiencing the following error:

 

[11:41:33] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.co
mmon.launcher.FMLInjectionAndSortingTweaker
[11:41:33] [main/INFO] [LaunchWrapper]: Loading tweak class name cpw.mods.fml.co
mmon.launcher.FMLTweaker
[11:41:33] [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.jar:?]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
~[?:1.7.0_65]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
~[?:1.7.0_65]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Sou
rce) ~[?:1.7.0_65]
        at java.lang.reflect.Constructor.newInstance(Unknown Source) ~[?:1.7.0_6
5]
        at java.lang.Class.newInstance(Unknown Source) ~[?:1.7.0_65]
        at net.minecraft.launchwrapper.Launch.launch(Launch.java:97) [launchwrap
per-1.9.jar:?]
        at net.minecraft.launchwrapper.Launch.main(Launch.java:28) [launchwrappe
r-1.9.jar:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.7.0
_65]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.7.0
_65]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1
.7.0_65]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.7.0_65]
        at cpw.mods.fml.relauncher.ServerLaunchWrapper.run(ServerLaunchWrapper.j
ava:43) [forge.jar:?]
        at cpw.mods.fml.relauncher.ServerLaunchWrapper.main(ServerLaunchWrapper.
java:12) [forge.jar:?]
Caused by: java.lang.SecurityException: Cannot replace the FML security manager
        at cpw.mods.fml.relauncher.FMLSecurityManager.checkPermission(FMLSecurit
yManager.java:30) ~[forge.jar:?]
        at java.lang.System.setSecurityManager0(Unknown Source) ~[?:1.7.0_65]
        at java.lang.System.setSecurityManager(Unknown Source) ~[?:1.7.0_65]
        at cpw.mods.fml.common.launcher.FMLTweaker.<init>(FMLTweaker.java:35) ~[
forge.jar:?]
        ... 13 more

[luacs1998]

Can we have your launcher log?

[MrJeeves]

Here you go! http://pastebin.com/RVn8q1vW download link is in the text

[LexManos]

However you are running minecraft is adding its own security manager to java, this is not supported. You should run minecraft normally.