title: Worklight 6.0 WL development Server not starting
body: <p><strong>When I try to start my worklight development server Which is running on Windows 8 OS It gives me below error.</strong> </p>
  
  <p>CWWKE0005E: The runtime environment could not be launched.
  CWWKE0018E: An exception occurred while launching the runtime environment: java.lang.IllegalArgumentException: WebSphere-DefaultExtension-windowsnt(unknown)
  com.ibm.ws.kernel.boot.LaunchException: Caught unexpected exception java.lang.IllegalArgumentException: WebSphere-DefaultExtension-windowsnt(unknown)
      at com.ibm.ws.kernel.boot.internal.KernelBootstrap.rethrowException(KernelBootstrap.java:412)
      at com.ibm.ws.kernel.boot.internal.KernelBootstrap.go(KernelBootstrap.java:179)
      at com.ibm.ws.kernel.boot.Launcher.createPlatform(Launcher.java:131)
      at com.ibm.ws.kernel.boot.Launcher.main(Launcher.java:55)
      at com.ibm.ws.kernel.boot.cmdline.EnvCheck.main(EnvCheck.java:52)
  Caused by: java.lang.IllegalArgumentException: WebSphere-DefaultExtension-windowsnt(unknown)
      at java.util.jar.Attributes$Name.(Unknown Source)
      at java.util.jar.Attributes.getValue(Unknown Source)
      at com.ibm.ws.kernel.boot.internal.BootstrapManifest.getOSExtensionDefinition(BootstrapManifest.java:146)
      at com.ibm.ws.kernel.boot.internal.KernelBootstrap.go(KernelBootstrap.java:122)
      ... 3 more</p>
  
  <p>Can someone please help me on this...</p>