How to Fix – unexpected end of data 7zip

If you have ever dealt with a compressed archive (i.e., .zip or .7z file) you will know that oftentimes an important part of the process is ensuring that the file you have can be successfully extracted. However, there are occasions when during the extraction process you will receive an error message such as an “unexpected end of data” error in 7zip. If this is the first time you ever see that message then you might be confused about what it is and how to address it. This guide will help you figure that out. 

What is an “unexpected end of data” error in 7zip? 

Essentially this error message appears when an archive file is either corrupted or incomplete and it will be an indicator that for some reason the archive had ended prematurely during the extraction. As this type of error could have a variety of causes there are also several solutions that you could use to address each of these causes based on what you believe is the most likely perpetrator. 

What are the causes and solutions of an “unexpected end of data” error in 7zip?

Problem with the archive copy 

The most common problem you will have with an archive that could result in this error is that for some reason the copy you have had some problem in either the compression process or the download. 

If the problem was in the compression process then you will need to access the original material that went into the compressed file and potentially re-compress them to get access to a version that has not been previously corrupted. 

If the original footage does not belong to you and was taken from someone else, or downloaded from the internet, then you will need to try and get another copy of that archive. As the problem could have occurred during the download or transfer process, likely, the new archive will no longer have the same error code. However, if it continues to show an error then the original files will need to be compressed again and sent to you. 

Mismatches in the file size

In some occasions, the reported file size within the archive material does not match the expected size. This variation could cause an issue with the extraction process. Once again, this is the type of issue that would require you to go through the compression process again. 

Archive Repair tools and Compression Tools 

There are certain archive formats, including .zip which have commands and tools available that will allow you to repair corrupted archives. As these are specific to the compression tool you are employing you will need to check for a tutorial on your tool to see the best way to fix this. 

Alternatively, you can also try to use a different compression and extraction tool if you find that the one you have been using has frequently caused you to have issues with your archive. 

Check for File Corruption

Use a checksum or hash function to verify the integrity of the file. By default, many websites provide checksums or hash values for their files. You can use tools like md5sum, sha1sum, or sha256sum to calculate the hash of the downloaded file and compare it with the provided hash.

Example:

We can use md5checksum to validate the integrity of a file

md5 example.txt

MD5 (example.txt ) = 87db9f80a1005e9a52c4b40ffb193533

You can check the md5 checksum value before and after sending/receiving the data and compare the value. any change in the value shows there is changes or corruption in the file

Update 7zip

Much like with using a different tool there is also the possibility that you are using an older version of the compression tool which has bugs and other issues that have been solved in a later update. For this reason, it is always a good idea to update to the latest version of your chosen compression tool and then check if you are still receiving an “unexpected end of data error”. 

Repair Tool

If the compressed file was created with the option to include recovery records, you may be able to repair the archive.

Open 7-Zip-> select the file and look for a “Repair” option. Follow the prompts to attempt to repair the archive.

Example: If you are using WinRAR you can follow the below steps

  • Open WinRAR
  • Find the corrupted file
  • ALT + s -> to select the file and to open the tool
  • Check “Treat the Corrupt Archive as Zip
  • Start the process -> Done when it completed

Storage device issues

There are some occasions when it is not the archive that has the issue but rather the storage or disk. If that is the case the disk might have not properly allowed for the transfer of the file, causing the error during the extraction process. This is why you should run a troubleshooter to check whether the storage device that has the archive has any issues that might have blocked the transfer.

Also, Make sure you have enough space in the disk to uncompress the file

Recover the corrupted 7z archive

Use the steps provided on the official 7z site to recover the file. Make sure you are using the latest 7zip software to recover the file

Steps to recover corrupted file: https://www.7-zip.org/recover.html

Conclusion

When dealing with an “unexpected end of data” error the most important thing to do is systematically check each of the components that might have resulted in that error. This includes the storage device, the transfer, the archive file, and finally the original files to determine where the issue was caused and fix it accordingly. 

Happy Learning!!

Jerry Richard
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