How to Resolve “Unable to Access Jarfile” Error on Windows PC

Some users have recently reported an error when launching certain applications when they get the “Unable to access jarfile” error message. Here I will explain how you can easily fix this error on your devices. Here you will learn how to remove Java Deployment Toolkit.

JAR is a batch file format extension that is used in Java class files to combine metadata and resources into one batch file for distribution. If the application running the Java class files cannot find or process the JAR file, this error message is displayed.

What causes the “Cannot access Jarfile” message?

  • You do not have the latest version of JAVA installed on your computer. In order to run JAR files efficiently, you need to have the latest version of the framework installed on your computer.
  • The default program to open JAR files is not defined.
  • There is malware on your computer that can disrupt the entire process.
  • The file path defined for the Java executable file is incorrect and indicates the wrong location. This error message may appear when you start your computer.

How to repair the “Cannot access Jarfile” error message?


Update Java to the latest version

  1. Go to the search option on the taskbar and type Run.
  2. Click on the Run dialog box, type appwiz.CPL, then press Enter,
  3. Go to the Control Panel, where you can uninstall and modify the program.
  4. Check your computer thoroughly and find Java, right-click on it to remove it.
  5. Go to the official Java website, download and install the latest version.
  6. Reboot your computer and check if the message about not being able to access the jar file persists or not.

Set Java as the default opening program

  1. Navigate to the folder containing your JAR files.
  2. Right-click on the JAR file and select “Open with”, then “Java Program”.
  3. Select another application if you don’t have a Java application displayed, and click Java in the list.
  4. Navigate to the Java folder and select Java to open it.
  5. You will have the option to open in a new window, click OK.
  6. Now open the JAR file and see if the problem persists or not.

Make hidden files and folders visible

  1. Bring up the File Explorer.
  2. Click on the View tab and then on Options to open the window.
  3. Select the View tab in the window.
  4. Select Show hidden files and click Apply.
  5. Select OK and check whether the problem persists or not. If not, go to the next option.

Set the default file association

  1. Navigate to the directory with the JAR file.
  2. Open the executable file with the JAVA program.
  3. Press Windows + I to launch the Settings application.
  4. Go to Apps and select Default Apps in the left navigation bar.
  5. Click Select Default Apps by File Type and look for the .jar file entry.

Frequently Asked Questions

In most cases it is because the jar file you are looking for is not in the jar folder or there is an invalid entry in the jar value on the server info page. If the correct jar file cannot be found, the server will crash until the problem is resolved.

Open File Explorer and the folder containing the file you want to run. Right-click on the JAR file and select Open with. Click Select Another Application, and then select Open with Java(TM) Platform SE Binary. Select the Always use this application to open JAR files checkbox.

  1. Use software that can open multiple file formats.
  2. Update the version of Java.
  3. Select Java as the default program for JarFiles.
  4. Select the option Show hidden files, folders, and drives.