How to Fix “File Upload Failed, File Contents Differ” Error in Minecraft

the “File download failed, content differs from what was expected” error in Minecraft can really disturb your mood. When this happens, you cannot access the game to explore the dungeons you planned to explore or exploit for hours in your virtual world.

We will go over different fixes to help you fix the problem if your Minecraft launcher also fails to download the file.

1. Listen to what the error message says

Consider providing the Minecraft launcher with what it asks for before implementing any other fixes. As the error window indicates, the contents of the file on disk are different from what the launcher expected, so manually downloading and adding the requested file may resolve the issue.

As the error message also specifies the URL from which the file should be downloaded and the location on your hard drive where you should add it, it makes your job much easier.

Before downloading the file and replacing it, copy the error message to a separate file to copy the paths when downloading and pasting the file. Then follow these steps:

  1. Copy the target URL mentioned below, paste it in any web browser and let the file download automatically.
  2. Copy the downloaded file and navigate to the file explorer path specified in the error message:
  3. Delete named file jopt-simple-4.5.jar and paste the downloaded one instead.


After replacing the file, restart the launcher to verify that the error has been resolved. Otherwise, unzip the downloaded file to the same folder you pasted it to earlier. If the error persists, let the copied file be placed in the directory and implement the fixes below.

2. Change preference for opening files with .JAR extension

A Java runtime environment is required to open .JAR files. You must set the appropriate open file preference for Java to execute all classes and resources in a .JAR file in a single request.

Files will not be executed if another application is set as default to open these files. This poor execution may also be responsible for the error in question.

To change it, follow these steps:

  1. Go to C: > Users > %username% > AppData > Roaming
  2. Move towards .Minecraft.
  3. Right-click any file with .JAR extension and select Properties. (In this case, we’re changing the open file preference using a .JAR file in the addons case).
  4. Right next to opens withclick on the Switch button.
  5. Select the Java (or JDK) to open these file extensions.

If you prefer, you can repeat the same process for any other file with the .JAR extension to change the file’s open preferences. However, you can skip this step if the file extension is already set to open in your desired file open preference.

3. Eliminate Corrupt Mod Issues

If you are a heavy Minecraft player who is not hesitant to try every new Minecraft mod you come across, a corrupted mod file can also lead to this problem. To rule this out, follow these simple steps:

  1. Navigate to the following path:
  2. Copy it mods folder and paste it somewhere else.
  3. Delete original mods folder from the game files.
  4. Run the Minecraft launcher again.

If deleting the mods folder fixes the problem, one of the mods is corrupt. First, you need to remove the mod you added recently. After that, you need to relaunch the launcher to see if the issue has been resolved.

The corrupted mod still resides in the game files when the problem persists. The best way to find the culprit is to delete each mod file from the mods folder one by one and run the launcher repeatedly. Filter and permanently remove the offending mod, and you’re done.

If removing all mods doesn’t work, continue implementing the fixes below.

If you’re primarily using a non-vanilla launcher with mods applied, chances are the launcher itself is causing the problem. Therefore, locate the folder where the non-vanilla launcher is installed and delete it and all its associated files. After that launch the vanilla launcher.

You should ditch the non-vanilla launchers and switch to the vanilla launcher permanently if launching with a vanilla launcher fixes the problem.

5. Whitelist Minecraft Launcher in Microsoft Defender Firewall

The Microsoft Defender firewall can also cause this error as it can prevent the launcher from downloading files properly. Therefore, whitelisting Minecraft in the firewall settings (allowing the app through the firewall) has a good chance of fixing the problem.

Follow the steps below to do so:

  1. Right click on Windows To start up button and go to Settings.
  2. Go to Update and security.
  3. Click on Windows Security in the left sidebar.
  4. Go to Firewall and network protection in the right pane.
  5. Click on Allow an application to pass through the firewall in the right pane.
  6. Click on the Modify the parameters then hit Allow another app… button.
  7. Click on Browse and locate the Minecraft launcher app.
  8. Then click Add.
  9. Check the boxes for Private and Audience.
  10. Hit OKAY.

If you want, you can also temporarily disable Microsoft Defender Firewall. Try running the launcher again to see if it downloads the file this time. If the error persists, reinstalling Minecraft is the best option.

6. Reinstall Minecraft

Since you need to remove the existing installation before reinstalling Minecraft, copy the Save folder from the game files and save it somewhere else to avoid losing your progress. Then open the Windows Control Panelclick on Programs and Featureslocate it minecraft launcherright click on it and select Uninstall.

Then go to C: > Users > %username% > AppData > Roaming and delete the “.Minecraft” case. Then take a copy of Minecraft from the official website and install it on your computer.

Don’t forget to copy the Save folder again in the exact location in a fresh install so you can continue playing the game while retaining previous progress.

7. Make sure the problem is not with Minecraft or report the problem to Minecraft

If the problem persists after applying all the fixes mentioned above, the problem may be with the backend of Minecraft. To confirm, go to Minecraft Bug Reporting Tool and check the most recent reported cases.

Whenever you find multiple reports about the same issue, you should wait for Minecraft to fix it automatically. If you are the only one having this problem, report it and listen to what they say.

Get back to exploring your Minecraft world

By applying the fixes above, you should be able to fix the “File download failed, content differs from what was expected” error in minecraft. If the problem persists, consider downgrading to an older version of the game.

Even if that doesn’t fix the problem, let the Minecraft launcher rest for a while and play classic Minecraft on the web. Although it has several limitations, it is a good alternative if you are eager to play the game.

How to play Minecraft for free in your browser

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