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First, it closes the launcher and shows on the screen: Error: A Java Exception has occurred. Then it goes back to the prompt and says:

Looking for old natives to clean up...
Unpacking natives to C:\Users\Owner\AppData\Roaming\.minecraft\versions\1.6.4_OptiFine\1.6.4_OptiFine-natives-13889915481012
Launching in C:\Users\Owner\AppData\Roaming\.minecraft
Running C:\Program Files (x86)\Java\jre7\bin\javaw.exe -XX:HeapDumpPath=MojangTricksIntelDriversForPerformance_javaw.exe_minecraft.exe.heapdump -Xmx512M -Djava.library.path=C:\Users\Owner\AppData\Roaming\.minecraft\versions\1.6.4_OptiFine\1.6.4_OptiFine-natives-13889915481012 -cp C:\Users\Owner\AppData\Roaming\.minecraft\libraries\net\sf\jopt-simple\jopt-simple\4.5\jopt-simple-4.5.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\paulscode\codecjorbis\20101023\codecjorbis-20101023.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\paulscode\codecwav\20101023\codecwav-20101023.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\paulscode\libraryjavasound\20101123\libraryjavasound-20101123.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\paulscode\librarylwjglopenal\20100824\librarylwjglopenal-20100824.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\paulscode\soundsystem\20120107\soundsystem-20120107.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\argo\argo\2.25_fixed\argo-2.25_fixed.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\org\bouncycastle\bcprov-jdk15on\1.47\bcprov-jdk15on-1.47.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\google\guava\guava\14.0\guava-14.0.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\org\apache\commons\commons-lang3\3.1\commons-lang3-3.1.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\commons-io\commons-io\2.4\commons-io-2.4.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\net\java\jinput\jinput\2.0.5\jinput-2.0.5.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\net\java\jutils\jutils\1.0.0\jutils-1.0.0.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\com\google\code\gson\gson\2.2.2\gson-2.2.2.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl\2.9.0\lwjgl-2.9.0.jar;C:\Users\Owner\AppData\Roaming\.minecraft\libraries\org\lwjgl\lwjgl\lwjgl_util\2.9.0\lwjgl_util-2.9.0.jar;C:\Users\Owner\AppData\Roaming\.minecraft\versions\1.6.4_OptiFine\1.6.4_OptiFine.jar net.minecraft.client.main.Main --username MathEnthusiast --session token:67bab057f3604b70b3b9e63d462f353a:a24042dab24549a8a36eb6db9344a7dd --version 1.6.4_OptiFine --gameDir C:\Users\Owner\AppData\Roaming\.minecraft --assetsDir C:\Users\Owner\AppData\Roaming\.minecraft\assets
Client> Exception in thread "main" java.lang.SecurityException: Invalid signature file digest for Manifest main attributes
Client> at sun.security.util.SignatureFileVerifier.processImpl(Unknown Source)
Client> at sun.security.util.SignatureFileVerifier.process(Unknown Source)
Client> at java.util.jar.JarVerifier.processEntry(Unknown Source)
Client> at java.util.jar.JarVerifier.update(Unknown Source)
Client> at java.util.jar.JarFile.initializeVerifier(Unknown Source)
Client> at java.util.jar.JarFile.getInputStream(Unknown Source)
Client> at sun.misc.URLClassPath$JarLoader$2.getInputStream(Unknown Source)
Client> at sun.misc.Resource.cachedInputStream(Unknown Source)
Client> at sun.misc.Resource.getByteBuffer(Unknown Source)
Client> at java.net.URLClassLoader.defineClass(Unknown Source)
Client> at java.net.URLClassLoader.access$100(Unknown Source)
Client> at java.net.URLClassLoader$1.run(Unknown Source)
Client> at java.net.URLClassLoader$1.run(Unknown Source)
Client> at java.security.AccessController.doPrivileged(Native Method)
Client> at java.net.URLClassLoader.findClass(Unknown Source)
Client> at java.lang.ClassLoader.loadClass(Unknown Source)
Client> at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
Client> at java.lang.ClassLoader.loadClass(Unknown Source)
Client> at sun.launcher.LauncherHelper.checkAndLoadMain(Unknown Source)
Game ended with bad state (exit code 1)
Ignoring visibility rule and showing launcher due to a game crash
Deleting C:\Users\Owner\AppData\Roaming\.minecraft\versions\1.6.4_OptiFine\1.6.4_OptiFine-natives-13889915481012