Windows 10
Type Control Panel into the Search the Web and Windows field
Click on Control Panel Desktop App at the top of the list
In the top right corner of the Control Panel, select Category View from the View By: pull down menu
Click Programs
Under Default Programs, click the Make a file type always open in a specific program link
Under the Name column, locate and select JNLP from the list of Extensions
Click the Change program button
Click more apps
Scroll down to the bottom and select Look for another app on this PC link