Optifine 1.8.1

Je viens de reboot mon PC entièrement et il m'arrive ça maintenant en tentant de lancer M 1.8.1 Opti

janv. 31, 2015 5:02:56 PM net.minecraft.launchwrapper.LogWrapper log
INFOS: Loading tweak class name optifine.OptiFineTweaker
janv. 31, 2015 5:02:57 PM net.minecraft.launchwrapper.LogWrapper log
INFOS: Using primary tweak class name optifine.OptiFineTweaker
janv. 31, 2015 5:02:57 PM net.minecraft.launchwrapper.LogWrapper log
INFOS: Calling tweak class optifine.OptiFineTweaker
OptiFineTweaker: acceptOptions
OptiFineTweaker: injectIntoClassLoader skipped, OptiFine is loaded as a library
OptiFineTweaker: getLaunchArguments
OptiFineTweaker: getLaunchTarget
janv. 31, 2015 5:02:57 PM net.minecraft.launchwrapper.LogWrapper log
GRAVE: Unable to launch
java.lang.ClassNotFoundException: net.minecraft.client.main.Main
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:179)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:344)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:127)
at net.minecraft.launchwrapper.Launch.main(Launch.java:27)
Caused by: java.lang.NullPointerException
at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:171)
... 6 more

Java HotSpot(TM) 64-Bit Server VM warning: Using incremental CMS is deprecated and will likely be removed in a future release