How to Resolve the “An Error Occurred While Unpacking: Does Not Match Checksum” Issue on Windows

Are you trying to install a game or software on your Windows 11 or Windows 10 computer and suddenly encountering an error that says, “An error occurred while unpacking: Does not match checksum”? It can be frustrating when this error message appears, especially when it’s accompanied by confusing DLL (Dynamic Link Library) errors involving files like ISDone.dll and Unarc.dll, along with a seemingly random error code, such as “-12,” which indicates a failed CRC (Cyclic Redundancy Check) check.

This common issue typically arises when you’re downloading games or software and attempting to run them. The root cause of the problem is usually that the extracted data doesn’t match the expected value. In simpler terms, it means that the file may be corrupted or didn’t download properly.

The good news is that, despite the technical jargon in these error messages, you can handle and fix them. In this article, we’ll break down these errors into plain language and provide you with step-by-step guidance on how to resolve them. So, let’s dive in and get your installation back on track.

Understanding the “Does Not Match Checksum” Error

Have you ever encountered the error message “An error occurred while unpacking: Does not match checksum” while installing software or unpacking compressed files, like game installations? It might sound technical, but let’s break it down in simple terms.

Think of a “checksum” as a digital fingerprint for a file. Just like every person has a unique fingerprint, every file has a unique checksum. This checksum is like a way for your computer to ensure that a file is in perfect shape, with no missing pieces or alterations.

So, when you see the error “Does not match checksum,” it means your computer compared the digital fingerprint of the file you’re trying to use with the fingerprint it expected to find. And guess what? They didn’t match! This mismatch can occur for a few reasons:

• File Damage or Corruption: It’s like buying a puzzle, only to find that a few pieces are damaged or missing. The file you downloaded might have been damaged or corrupted during the download process.
• Missing Parts: Some parts of the file may be missing altogether. Just like a puzzle with missing pieces, your computer expected the full file but didn’t find it.
• Glitches: Sometimes, there can be glitches in the process of checking the file. These glitches can throw off the digital fingerprint comparison.
• Missing Components: Another reason for this error could be missing components needed to install or unpack the game or software, such as the Microsoft Visual C++ redistributable packages.

In essence, this error message is like your computer’s way of saying, “Hey, something’s not right here!” It’s similar to expecting a complete puzzle but discovering that a few pieces are missing or damaged. But don’t worry, we’ll show you how to fix these issues and get your software installation or file unpacking back on track.

How to Fix “An Error Occurred While Unpacking; Does Not Match Checksum”

Encountering the “An error occurred while unpacking; Does not match checksum” or “Unarc.dll returned Error Code 12” error can be frustrating. Fortunately, you can resolve this issue by following these steps:

Solution 1: Verify Your Installation Media

As mentioned earlier, this error often occurs when the file is corrupted or hasn’t been downloaded correctly. To tackle this issue, you should verify that your installation media is not corrupted.

1. Re-download the File: The first and simplest step is to re-download the file. Sometimes, the download process itself may have caused corruption. Re-downloading the file ensures you have a fresh and intact copy.
2. Check File Integrity with Hash Values: If re-downloading doesn’t solve the problem, you can check the file’s integrity using hash values. The hash value is like a digital signature that ensures the file’s authenticity. Here’s how to do it:
   • Look for the hash value on the download page. It’s usually provided in MD5 or SHA-256 format.
   • Use a tool like Certutil or HashMyFiles to open the file.
   • Compare the hash value from the download page with the one your software shows. If they don’t match, it’s a clear sign that the file is corrupted.
3. Try Another Source: If you find a mismatch in hash values, it’s advisable to download the software from another trusted source. The source you initially used may have a corrupted version of the file.

By following these steps, you can ensure that your installation media is not corrupted, which should resolve the “Does not match checksum” error and allow you to proceed with your installation without any hiccups.

Solution 2: Verify the Integrity of Your Installation Files

When faced with the “Does not match checksum” error, one of the most critical steps to resolve it is ensuring that your setup and installation files are free from corruption or missing components. Here’s what you can do:

Re-download the Installer

If you’ve come across this error, there’s a possibility that the file you downloaded is either incomplete or corrupted. To begin resolving this issue, follow these steps:

Start by re-downloading the installer or compressed package from the official and trusted source. It’s essential to use a stable internet connection to avoid potential corruption during the download process.

Check File Integrity with Hash Values

Especially for larger files like games or software, websites often provide something known as a “hash value.” These values, which come in formats like MD5 or SHA-256, serve as digital fingerprints for the files, allowing you to verify their integrity.

To ensure that your downloaded file is in good condition:

• Use tools available online or software like “HashMyFiles” to compute the hash for your downloaded file.
• Compare this calculated hash with the one provided on the official website.
• If the hash values match, you’re in good shape! The file is intact and uncorrupted. However, if they don’t match, it’s an indicator of potential corruption, and you should consider downloading the file again from a reliable source.

By following these steps, you can confirm the integrity of your installation files, significantly reducing the chances of encountering the “Does not match checksum” error and ensuring a smooth installation process.

Solution 3: Install Microsoft Visual C++ Redistributable 2013

Many users have reported success in resolving the “An error occurred while unpacking: Does not match checksum” issue by downloading and installing Microsoft Visual C++ Redistributable. This solution can be effective because sometimes the problem isn’t with the file itself but with the tools and components your computer uses to unpack it. Here’s how to do it:

Step 1: Download Microsoft Visual C++ 2013 Redistributable: Visit Microsoft’s official website and download the Microsoft Visual C++ 2013 Redistributable package. Be sure to choose the appropriate version (x86 or x64) based on your system architecture.

Step 2: Install Microsoft Visual C++ 2013 Redistributable: Double-click the downloaded file to initiate the installation process. Follow the on-screen instructions provided by the installer to complete the installation.

Step 3: Run .exe File: After the installation, you may want to run any .exe files included in the package one by one and follow the on-screen instructions for each to ensure that all components are properly installed.

Step 4: Reboot Your PC: Once you’ve completed the installation of Microsoft Visual C++ 2013 Redistributable and any associated .exe files, restart your computer.

Step 5: Continue with Game or Software Installation: After rebooting, proceed with the installation of your game or software. The “An error occurred while unpacking: Does not match checksum” issue should now be resolved, and you should be able to install your software without any problems.

For a more comprehensive solution that covers multiple versions of Visual C++ Redistributables, you can consider using the “VisualCppRedist_AIO_x86_x64.exe” package available on GitHub. This package is maintained by a trusted developer and includes a wide range of Visual C++ Redistributable versions. Here’s how to use it:

Step 1: Download “VisualCppRedist_AIO_x86_x64.exe” Package: Download the “VisualCppRedist_AIO_x86_x64.exe” package from GitHub.

Step 2: Run the Package as Administrator: Run the downloaded file as an administrator. This package will install multiple Visual C++ Redistributable versions, ensuring that your system has all the necessary components for software installations.

By following these steps, you can resolve the “Does not match checksum” error and ensure that your system is equipped with the required components for smooth software installations.

Important Tips and Precautions

While the solutions provided above can often resolve the “Does not match checksum” error, it’s essential to follow some general precautions and consider additional tips to ensure a smooth installation experience:

• Ensure a Stable Internet Connection: A reliable internet connection is crucial when downloading files to avoid incomplete or corrupted downloads. If possible, use a wired connection, especially when downloading large files. If you’re using Wi-Fi, ensure that your signal is strong and stable to prevent interruptions during the download process.

• Use Official Sources: Always download software and games from official and reputable sources. Avoid third-party websites or torrents, as they may host modified or corrupted files that can trigger the “Does not match checksum” error.
• Keep Your System Updated: Regularly update your operating system and drivers to ensure compatibility with the software you’re installing. Outdated software can sometimes lead to compatibility issues.
• Maintain Adequate Storage Space: Make sure your computer has enough available storage space for the installation. Lack of space can cause problems during the unpacking process, leading to the error in question.
• Run as Administrator: When installing software, it’s often a good practice to right-click on the installer and select “Run as administrator.” This ensures that the installation process has the necessary permissions to modify system files.
• Disable Antivirus and Firewall Temporarily: Sometimes, antivirus software or firewalls can interfere with the installation process. Temporarily disable them while installing the software and re-enable them afterward to avoid any conflicts.
• Create Backups: Before making significant changes to your system, such as installing or uninstalling software, consider creating backups of your important files and data. This precaution can help you recover in case anything goes wrong during the installation.
• Read User Reviews and Forums: If you’re encountering persistent issues with a particular software or game, check user reviews and online forums for troubleshooting tips and to see if others have experienced similar problems.
• Contact Support: If none of the solutions work or if you’re unsure about taking certain actions, don’t hesitate to contact the official support channels of the software or game. They can provide guidance tailored to your specific situation.

By following these tips and precautions, you can enhance your installation experience and minimize the chances of encountering the “Does not match checksum” error or related issues.

Conclusion

Dealing with errors, particularly during software installations, can indeed be frustrating and can feel like unexpected roadblocks on a journey you were excited about. The “Does not match checksum” error, despite its technical-sounding name, is essentially your computer’s way of telling you that something isn’t quite right with the file you’re trying to use. While this error might initially seem complex, it often boils down to issues like file corruption or compatibility problems.

The good news is that these issues are generally solvable. By either re-downloading the setup files or installing the necessary redistribution packages, you can clear the path and proceed with your installation smoothly. Remember, technology hiccups are a part of the digital landscape, but with the right knowledge and troubleshooting steps, you can overcome them and continue your journey without unnecessary delays.