Unable to Access Jarfile Minecraft Server Error [Solved]

Are you getting the “Unable to access Jarfile” error prompt when setting up a custom Minecraft server? You may also encounter the error when you attempt to open a .Jar package. The error message means that the Jar file cannot be found. 

In most cases, this happens when the .Jar handlers are not configured correctly. It could also mean that the .Jar file is not located where it is supposed to be in the JAR folder. Other things that are commonly associated with the error include an outdated Java version, and wrong file path. 

If you are unable to access jarfile in Minecraft or any other Java-based application, this guide will help you fix it in just a few minutes. 

What is JAR?

JAR is an acronym for Java Archive—a file format that is based on ZIP. The package file format is used to group multiple Java class files with their associated resources, and metadata into a single package. The files are grouped for the purpose of distribution. 

To open JAR files, you must have the Java Run-time Environment (JRE) installed on your computer. Even so, only the executable JAR files can be opened. 

What Causes the Unable to Access Jarfile Error? 

The unable to access Jarfile Minecraft error prompt mag be triggered by different things, most of which relate to how the Jar Files are handled on the computer. Are you unable to access Jarfile on Windows 10, Linux, or just can’t launch JAR file on Mac? 

Discussed below are some of the things that are known to trigger the error message: 

Required Jar File is Missing 

Are you getting the error message when you try to launch the Minecraft game? If so, chances are that the Jarfile set in Multicraft is not currently in the correct location, within the JAR folder. Again, you may get this error message when the file path for the Java executable is not configured correctly. 

In such a case, the system will end up hitting the wrong location for the Jar executable file.

Default Program not Set 

In other cases, the error can occur simply because you have not configured the right program to open Jar files by default on your PC. 

Server Jar Installer Issues 

Other users are getting the “unable to access Jar file” error message when attempting to upload and set up a custom panel. In most cases, this occurs when the panel tried to look for a custom server version that is not currently supported by your Server Jar Installer. 

Again, the system may be unable to access the relevant Jar file simply because the Jar value entry on the server details page is invalid. If you would like to use a custom Jar file, ensure that the file is named correctly. 

Simply log into your FTP panel on Minecraft and check whether the name of the Jar file is set to ‘my.jar’.

Outdated Java Version

If you are getting this error message following an update of the Minecraft game, it may be as a result of software incompatibility. The newer version of the game you just installed may require a different Java application version to run. 

In this case, you need to update the Java App on your computer to the latest version fix the unable to access Jarfile error on Windows 10.

How to Fix the Unable To Access Jarfile Error 

Did you encounter this error message while setting up a Minecraft server? To begin with, you should find a valid entry to use within your JAR folder. In most cases, you will find that the Jar file is labeled something different from what the server is looking for, i.e. Minecraft-1.10.2.jar

If this is the problem, you need to rename the Jar file into what the panel is looking for, through your FTP panel. If this does not appear to be the problem, you should try the following methods to troubleshoot and fix the unable to access Jarfile error:

Method 1: Install the Latest Java Version

One of the common triggers of the “unable to access Jarfile” error message is an outdated Java version. To be on the safe side, you need to ensure that you are running the latest version of Java on your computer. To update the program, press the Windows + R keys simultaneously to open a Run dialog box. 

Type appwiz.cpl into this dialog box and press the Enter key. This operation will open the ‘Programs and Features’ menu window. On the list of installed programs, scroll down to the Java option, right-click on it and select Uninstall. 

Follow on-screen prompts to remove the program from your PC. Once done, close the window and navigate to the official Java website to download the latest Java installation file. After downloading, double-click on the executable file to run it. Follow the on-screen prompts to complete the installation. 

Method 2: Check for Relevant Documentation (Applies to Developers) 

As developers, you may encounter this error message when you attempt to launch JAR files while coding. In this case, it is advisable that you first read the documentation for the utility or function you are using to run JAR files. 

Reading the relevant documents ion will help you know whether you had been passing incorrect parameters or just using the wrong file path for the Jar files. Some of the leading coding websites, such as Stack Overflow, probably have a demo for the utility/functionality you are trying to implement. 

These will help you know where you went wrong, fix the problem, and successfully clear the “unable to access jarfile” error message. 

Method 3: Fix Unable to Access Jarfile Windows 7 Error (Set the Default File Association) 

Whether you are running Windows 7 or Windows 10 on your PC, you may get this error simply because Java is not set as the default Jar files handler. While various archiving programs may be configured to open Jar files by default, not all will produce the desired results, especially with the Minecraft game. 

To fix the problem, you need to change the file association for JAR files on your computer. The following procedure will help you achieve that: 

Step One: Configure the ‘Open With’ Settings 

Open the directory where the problematic Jar file is saved, and right-click on it. From the context menu that appears, choose the ‘Open With’ option. This will display a list of programs you may use to open/run Jar files. Select Java from this list. 

If Java is not readily available in this list, select the ‘Choose another App’ option, and then proceed to select Java. 

Step Two: Set the Default Association Permanently 

Press the Windows + I keys on your keyboard simultaneously to open the Settings Menu. Navigate to Apps, and then choose ‘Default apps’ from the left navigation bar on your screen. Scroll down and select the ‘Choose default apps by file type’ option towards the bottom. 

Now find the .jar files entry and ensure that it is configured to be opened by Java. Once you are done, save the changes and exit the window. At this point, you need to restart the computer and check whether the error has cleared. 

Method 4: Configure the Show Hidden Files, Folders, and Drives Settings 

If the system is not configured to show hidden files, folders, and drives, you may also end up getting the “unable to access Jarfile” error on Minecraft. To change the settings, open File Explorer on your Windows PC, and click on the View tab. 

Next, click n the options button to reveal a window directory. From this directory, select the View tab that appears directly below, and then choose the “Show Hidden Files, Folders, and Drives Files and Folders” option.

Having made the selection, click on the Apply button to save the changes, and then click on OK to close the window. 

Method 5: How to Fix the Unable to Access Jarfile MacOS Problem 

This inability to open Jar files is also known to plague Mac computers. If you can’t launch a JAR file in Mac, the problem could be the Java Virtual Machine, or the launcher itself. The problem may also occur when you are connected through SSH, and the machine user is not logged in. 

Here are some of the solutions you may apply to fix the unable to access Jar file on Mac OS: 

Run the .Jar File form the Terminal 

Provided that the .Jar file is properly constituted, running it from a Terminal is the best workaround for this issue. To run a Jar file from the Terminal, press the Control + Option + Shift + T keys simultaneously to open a new Terminal. 

Now type $ java -jar filename.jar into the new Terminal and press the Enter key. You can now check to see if the problem has been resolved. 

Run the .jar File in the Console

Running the problematic Jar file directly in the Console will display an error message. This error message will include a reason why you are unable to run the .jar file on your Mac computer. The message will also feature tips on how you can debug the problem. 

Just read through the error message and try to apply the recommended fixes. 

Final Verdict 

You may get the unable to access .Jarfile Minecraft server error on both Windows and Mac computers. Normally, it occurs when you try to apply a custom server version on your panel. There are multiple other scenarios, under which you may get this error message, as you have learned throughout this guide. 

The right solution for the problem will depend on what is actually triggering the error message. Regardless of the cause, the procedures illustrated above will help you resolve the unable to access .Jarfile error in Windows and Mac OS.

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