Mac OS X 10.5: Unable to launch Java Web Start JNLP file after installing Java Update

After installing a Java software update, Java Web Start JNLP document files may lose their association with the Java Web Start launcher application, and may open using another application instead, or not launch at all.

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To re-register JNLP files with Java Web, use one of the following methods:

  1. In the Finder, open the /System/Library/CoreServices folder. Simply opening this folder will re-associate JNLP files with Java Web
  2. Close the CoreServices Finder window.


  1. Open Terminal (located in /Applications/Utilities/).
  2. Type or paste the following command, then press Return:
  3. /System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister "/System/Library/CoreServices/Java Web"

  4. Close the Terminal window
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