ZIP and RAR two popular archive file formats which support lossless data compression. They both can contain your data and files in a compressed form so you get more free space on your hard disk. Unfortunately, any of these archive files are not immune to corruption like any other computer file. If a ZIP file is corrupt, you can’t extract anything from it. In such a situation, you must repair ZIP file so that you can extract your data. In this post, I’m going to show you how to repair corrupted archive file like ZIP and RAR.
Data Compression – Its Types
Data compression refers to a method or a process of compressing the files by reducing their size in order to save more free space on a hard disk. Unlike uncompressed files, if you’re using compressed files, they significantly take less storage space on your storage device, be it a system hard disk or any external storage media like a USB drive. Generally, data compression is of two types: lossless compression and lossy compression. Both are different from each other. How?
Lossless Compression: The algorithms of lossless compression search for long strings of code, so that shorter strings can easily replace them. It can recreate the entire file exactly same as it was before compression.
Lossy Compression: The algorithms of lossy compression search through the code in order to find the pieces which you can delete. It actually reduces the file size by permanently eliminating certain information, especially redundant information.
Benefits of Data Compression
There are many benefits of data compression. Below are common benefits:
- Data compression can easily reduce the amount of space needed for data storage.
- You can use data compression for any type of computer files.
- You can increase data transmission speed by using data compression.
- Data compression also provides data security.
- You can reduce the disk space on Internet server with the help of data compression.
Compressed Files Types
There are different compressed file types used by computer users, such as ZIP, RAR, TAR, TAR.Gz, and 7z.
ZIP (File type – Zipped File)
ZIP is the most popular compressed cum archive file format created by WinZip and WinRAR utilities. It contains one or multiple files in compressed form. ZIP archive stores multiple files separately from each other and compress them by using different methods. You can extract files from a ZIP archive without compressing or decompressing the entire archive.
RAR (File type – WinRAR Compressed Archive)
RAR is also an archive cum compressed file format just like ZIP. It uses RAR compression to compress one or multiple files. RAR archive is created by WinRAR which uses a higher compression ratio than ZIP compression. You can extract data from RAR archive by using a variety of programs.
TAR (File type – Consolidated Unix File Archive)
TAR is an archive file format created by TAR utility, a Unix-based utility for packaging multiple files together in uncompressed form. The TAR utility creates an archive which contains a large number of files. Unlike other archive file formats, it doesn’t compress the files.
TAR.Gz (File type – Compressed Tarball File)
TAR.Gz is a TAR archive compressed with the standard GNU-ZIP (gzip) compression algorithm. A TAR.Gz file can contain one or more compressed files. It includes both TAR and Gz file types. It’s commonly used in Unix operating systems for packaging files, programs, and installers. To open or use TAR.Gz archive, first, you must decompress it and then expand it by using TAR utility.
7z (File type – 7-Zip Compressed File)
7z is a compressed archive file format created by 7-Zip compression utility. Though users don’t often use this archive format, it’s much better than other formats. It uses an open-source LZMA aka Lempel–Ziv–Markov chain algorithm compression which provides high compression ratio and strong AES-256 (256-bit) encryption. A 7z archive file can be up to 16,000,000,000 GB of size. Other than LZMA (by default), 7z supports PPMD, BCJ, BCJ2, BZip2, and Deflate compression methods.
Corrupted Archive File
Though data compression provides you vast benefits, a compressed file is prone to corruption just like any other computer file. There are numerous reasons highly responsible for corruption in archive files, such as virus attack, sudden power outage, abruptly system shutdown, hard disk crash or failure, interrupted Internet connection during uploading or downloading archive file, software malfunction or failure, and many others.
Whenever a ZIP file is corrupt, you’re likely to receive an error message like “unexpected end of archive” or any other.
How to repair ZIP file and/or RAR file?
The best thing you can use to repair ZIP file or repair RAR file is the WinRAR application. It has a built-in repair feature that can repair corrupted archive file and open it. You just need to follow these simple steps:
Step 1: Launch the WinRAR application on your system.
Step 2: Now click on File tab > Open.
Or, you may simply press Ctrl+O.
Step 3: A small window “Find Archive” will pop up.
Locate the corrupt ZIP archive in your system directory, and click Open to select it.
Step 4: On the taskbar, click Tools tab > Repair archive.
Or, you may simply press Alt+R buttons.
Step 5: Again a small window “Repairing File name.zip” will pop up.
Click Browse to select a location to save the archive. Also, define the archive type before you can start the repairing process. For e.g. if you want to repair ZIP file, check the Treat the corrupt archive as ZIP option, or check the Treat the corrupt archive as RAR option to repair RAR file. Click OK.
Step 8: WinRAR will start repairing corrupt archive.
It takes just a couple of minutes to repair archive file. Click Close.
You can now check your repaired archive file.
Data Extraction from Corrupt Archive File
There’s one more thing you can do here manually to repair ZIP file or RAR file. But make sure the corrupt ZIP or RAR archive doesn’t contain large software’ executable files. If you’re having multiple images, audio, video, email, document and other types of files, you can try this trick before purchasing any paid software to repair ZIP file.
Step 1: First, launch the WinRAR application on your system. But don’t open the corrupt ZIP or RAR archive.
Step 2: Locate the corrupt archive you want to repair, but don’t open it. Right-click it to select the archive from the list.
Now click the “Extract To” icon on the taskbar.
Step 3: On the “Extraction path and options” window, select a location where you want to decompressed archive.
Don’t forget to check Keep broken files box under Miscellaneous option.
Step 4: Click OK to begin the data extraction process. This will extract all the files from the corrupt archive.
Note: You can only extract those files which are not broken or corrupt.
Professional Solution – Archive Recovery Software
If the above manual trick fails or doesn’t work, then you need to try a professional recovery solution. There are many software vendors in the market which provide 3rd party tools to repair corrupted archive file like ZIP and RAR. SyInfoTools Archive Recovery Software is one of the best recovery tools available in the market. It supports all 5 popular archive file formats, such as ZIP, RAR, TAR, TAR.gz, and 7z. With this software, you can successfully fix error messages like “unexpected end of archive”. You must download its demo version for free evaluation. Via the demo version, you can scan the corrupted archive file and check the preview of your data which you can actually recover from it.