I cannot open a JNLP file. What should I do? Help!

Virtually anyone has encountered some problems with opening unknown files while working on a computer. It can be very frustrating. Yet such problems, not only with JNLP files, can be addressed in a standard way. Follow the steps below and we can guarantee that your problem with opening JNLP will be resolved!

JNLP File Extension

  • File type Java Web Start Format
  • File developer Oracle
  • File category Web Files
  • File popularity rating
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What is a(n) JNLP file?

An Internet file with the extension .JNLP allows you to run and use Java programs in your web browser. It stores data in XML format regarding the remote address for downloading the Java program (.JAR file) and the initial class for running it using the JRE.


How to open JNLP file?

If given user account does not have necessary permissions to open files with JNLP extension, it is highly probable that no program that supports given files is installed on the users’ system. Below is a list of actions user should pursue in order to resolve most common problems.

Step 1. Download and install application that supports JNLP files

After the application has been installed, the system should automatically open JNLP files with given application. Below is the list of relevant programs along with operating systems they are available for:

Programs that support JNLP files

Step 2. Verify whether JNLP files are associated with appropriate software

It is possible that an application that supports JNLP files is not associated with such files. In such case, the program should by manually associated with JNLP files (right-click on the file icon → PropertiesGeneral Tab → In submenu "Open with" and click on "Change" button. System will display a list of suggested programs that support JNLP files. Choose the application by checking the box "Always use the selected application to open this kind of files". System will store this information in its registry and use it to open JNLP files with the selected program.

Changing JNLP file association in registry

File association for JNLP files can be edited manually by editing appropriate entry in Windows System Registry. However, it is discouraged as it may introduce errors to registry if not done properly and may even damage the system.

Step 3. Check JNLP file for other errors

  • JNLP file was not copied properly from storage medium.
  • Antivirus application prevents opening JNLP files. In that case it is recommended to exercise extreme caution and recover or delete infected JNLP file. It is also advised to scan the entire system for malicious software and viruses with antivirus software.
  • For JNLP files downloaded from the internet it is advised to check if the file has been downloaded completely and is not corrupted. If not, the file should be re-downloaded.

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