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 can get more free space on your hard disk drive. Unfortunately, any of these archive files are not immune to corruption like other computer files. You can’t extract anything from a corrupt archive file. You must repair ZIP file or RAR file so that you can extract your data. In this blog post, we’ll read about two different solutions to repair archive files like ZIP and RAR.
File & Data Compression – Its Types
File compression, aka 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 system hard disk or any external storage media like a USB drive. Generally, there are two main types of compression: lossless and lossy, and 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 File Compression
- File compression can easily reduce the amount of space needed for data storage
- You can use file compression for any type of computer files
- You can increase data transmission speed by using file compression
- File compression also provides data security
- You can reduce the disk space on Internet server with the help file compression
Types of Compressed Files or Archives
There are different types of compressed files or archives 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.
Though file compression provides you vast benefits, a compressed file is prone to corruption like every other computer file. There are numerous reasons which are 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.
How to repair ZIP file and/or RAR file?
The best thing you can use to repair ZIP file or repair RAR file is WinRAR application. It has a built-in repair feature that can repair corrupt archive and open it. You just need to follow the steps (shown below)
Step 1: Launch 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: Click on 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: Launch 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 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 companies in the market which provide 3rd party ZIP recovery and RAR recovery tools. You can try few of them. Or you can download free demo version of Archive Recovery Software. This software doesn’t only support only one or two archive formats. In fact, it supports all 5 popular archive cum compressed file formats, such as ZIP, RAR, TAR, TAR.gz, and 7z. You must download its demo version for free evaluation. You can check the preview of recovered data in the demo version. To save them, you’ll need its licensed version.