How to Fix the “Failed to Download File, the File Contents Differ” Error in Minecraft?

Did you encounter the “Failed to download file, the contents differ from what was expected” error in Minecraft? If you did and needed a fix, you’ve come to the right place. First, let me brief you on this error; when this happens, you cannot access the game to explore the dungeons you had planned to explore or mine, which is a complete bummer.

After being pestered for hours by my brother, l just had to go over different fixes to fix the problem, so if your Minecraft launcher is also unable to download the file, try following the mentioned fixes.

1. Listen to What the Error Message Says

The obvious option is to feed the Minecraft launcher what it’s asking for before trying other ways. However, as the error said, the file content on the disk differs from what the launcher expected, so downloading and manually adding the requested file might solve the issue.

As the error message also specifies the URL from which the file is to be downloaded and the location on your hard drive where you need to add it, it makes our job way easier.

Before you download and replace the file, copy the error message in a separate file to copy the paths while downloading and pasting the file. Then:

Copy the target URL mentioned below, paste it into any web browser, and the file will begin downloading automatically.

https://libraries.minecraft.net/net/sf/jopt-simple/jopt-simple/4.5/jopt-simple-4.5.jar

Copy the downloaded file, then navigate to the File Explorer path specified by the error:

C:\Users\<username>\AppData\Roaming\.minecraft\libraries

et

f\jopt-simple\jopt-simple\4.5\

Here, delete the file named just-simple-4.5.jar, then paste the downloaded one.

After you replace the file, restart the launcher to verify that the error has been resolved. If the problem isn’t solved, unzip the downloaded file in the same folder you pasted it in. If the error persists, keep the copied file in the directory, then implement the below fixes.

2. Change the Opening Preference of Files With the. JAR Extension

Note – A Java runtime environment is required to open. JAR files. 

You have to set the proper file opening preference for Java to execute all classes and resources of a . JAR file in one request.

The files will not be executed if any other application is set as default to open them. The improper execution could also be responsible for the error.

To change the default, follow the steps:

• Make your way to C: > Users > %username% > AppData > Roaming.
• Go to .minecraft.
• Right-click on any file with the. JAR extension, then click on Properties. (You will change the file opening preference using a . JAR file in the addons folder).
• Click on the Change button; it is situated right next to Opens With.
• Select the Java (or JDK) option to open such file extensions.

If you wish, you could repeat the same process for any other file. JAR extension to modify the opening preferences. However, you can skip this step if the file extension is already set to open in your desired opening preference.

3. Rule Out Launcher-Related Issues

If you are primarily using a non-vanilla launcher that has mods applied, the chances are that the launcher might just be causing the issue. Therefore, locate the folder where the non-vanilla launcher is installed, then delete it and all its associated files. After that, launch the vanilla launcher.

You should abandon the non-vanilla launcher and permanently switch to the vanilla launcher if launching a vanilla launcher has resolved the issue.

4. Rule Out Corrupted Mod Issues

If you are a power Minecraft player who does not hesitate to try out every new Minecraft mod you found, it could be possible that a corrupt mod file has led to this issue. To rule it out, follow:

Visit the following path:

C:\Users\%username%\AppData\Roaming\.minecraft

Copy the mods folder, then paste it elsewhere.

After copying, delete the original mods folder from the game files.

Re-Run the Minecraft launcher.

If doing this solved the problem, then it can be deduced that one of the mods was corrupt. So, as a start, you should delete the mod you added recently. After that, you should re-run the launcher to see if the problem is resolved.

The corrupted mod will still reside in the game files when the issue is not resolved. Therefore, the best way to find the culprit is to remove every mod file from the mods folder, then launch the launcher. Then, filter out to remove the offending mod permanently, which could be consuming if you have a large consignment of mods.

If deleting all mods does not help, continue with the below fixes.

5. Reinstall Minecraft

Well, sometimes, the best fix is just to reinstall the game. As you must delete the existing installation before reinstalling Minecraft, copy the Save folder from the game files, then save it elsewhere to avoid losing progress. Later, open the Windows Control Panel, click on Programs & Features, find the Minecraft Launcher, right-click on it, then click Uninstall.

After doing so, navigate to C: > Users > %username% > AppData > Roaming, then delete the “.minecraft” folder. Afterward, grab a copy of Minecraft from the official website, then reinstall it on your computer.

Make sure you copy the Save folder in the exact location in a fresh installation so you can continue playing the game while retaining your progress.

6. Allow the Minecraft Launcher in Microsoft Defender’s Firewall

Microsoft Defender’s Firewall can also be causing the error because it can prevent the launcher from downloading the files properly. Therefore, whitelisting Minecraft in the Firewall settings has a good chance of resolving the error.

Follow the steps below:

• Right-click on the Windows Start button, then open Settings.
• Navigate to Update & Security.
• Click on Windows Security; it is in the left-sidebar.
• Visit Firewall & network protection in the right-hand pane.
• Click on the option that says Allow an app through the Firewall.
• Click on the Change settings and the Allow another app button.
• Click on Browse, then search for the Minecraft launcher app.
• Then, click on Add.
• Check the boxes for Private as well as Public.
• Click OK.

If you wish, you also can disable the Microsoft Defender Firewall temporarily. Then, you can try running the launcher again to see if the files are downloaded this time. If the error persists, then reporting it to Minecraft is the best option.

7. Ensure the Problem is not from Minecraft or Report this Issue to Minecraft

If the problem persists despite applying all of the fixes mentioned above, the issue might be from Minecraft’s end. To confirm this, visit the Minecraft bug reporting tool, then check the most recent cases reported.

If you find multiple reports about the same issue, it is better to wait until Minecraft automatically resolves the issue. However, if you are the only one having this problem, report it to hear what Minecraft says.

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