Since JNLP files are simply Java Web Start files that open applications through an Internet browser, any browser that works in Windows 8.1 will open a JNLP file as long as you have Java installed.

To fix the JNLP file not opening problem, update or install Java Runtime Environment, set JRE as the default app, or install JRE 64-bit.

Once installed, navigate to the website hosting the JNLP file, and the JNLP Runner extension will automatically activate. A new Chrome tab will open, and after agreeing to the license, you'll see the ...

net.sourceforge.jnlp.LaunchException: Fatal: Launch Error: Could not launch JNLP file. The application has not been initialized, for more information execute javaws/browser from the command line and ...