Corrupt RAR archives are quite common online, so common in fact that recovery records are often included when files are being compressed and PAR2 files are extremely popular on Usenet to fight against corruption. When you get a corrupt RAR file it can be very annoying, but here are a few possible solutions to the problem.
Introduction & Requirements
|Software you must download and install|
|Optional: You probably already have it installed if you are using RAR files but if you don't, WinRAR is a powerful file archive utility. It can extract broken contents or repair with a recovery record. Download!|
|Optional: This one is specifically for corrupt RAR files from Usenet where PAR2 files might be posted with the file(s) to recover in the event of corruption. Download!|
WinRAR should be installed if you use RAR files anyway. It can recover a broken RAR archive in many cases, especially if a recovery record exists. It will even work with split RARs if the recovery record exists, just open the particular volume that is giving trouble and attempt repair as shown below.
QuickPar is simply added for those with access to Usenet who can find the same RAR file posted online with PAR2 recovery blocks present. This probably won't be the case for most people but in the event it helps, I decided to include it.
Above is an example of a RAR file error. In this case, it is "Unexpected end of archive", which means the file is either incomplete or is corrupt in such a way as to be unreadable past a certain point. Also note that it specifies "part10" in the filename. This means that the corrupt RAR is part of a group of split RAR files. To attempt to fix this problem with WinRAR if a recovery record was made and is present, then open part10. If your file isn't split, then proceed as normal.
Attempt WinRAR Repair
On your keyboard, hold down ALT + R for the program to bring up the Repair prompt. Otherwise, click Tools and select Repair Archive from the drop-down menu. When the Repair prompt comes up, you will have the option to treat the archive as a ZIP file or as a RAR file. Obviously select RAR and click OK. The program will now attempt a repair.
Recover Record Found?
If the program states that a recovery record is found then you have a much better chance of getting a successfully repaired RAR file. Even if it is not found, rebuilding the file anyway might yield some results. You might see the program list files it has found in the archive as it rebuilds a new archive that hopefully will be corruption free.
Incomplete rars can be notorious to fix. But there is another option too. For example, if you receive CRC errors at the very end of an extraction, then there is a option to "Keep Broken Files" in WinRAR that might allow you to attempt to repair the broken file that is extracted instead of repairing the WinRAR archive.
Keep Broken Files
If WinRAR does not succeed in getting rid of the annoying errors, then you can still attempt to extract the content in the RAR file. Select whatever files you want to extract specifically, and then click the "Extract To" button. The "Extract Path and Options" window will appear. Note from the screenshot above that Keep broken files has been ticked.
Usually if WinRAR runs into an error during extraction it will automatically discard anything it has already extracted. With Keep broken files kept selected, this won't happen. The files will output to whatever folder you specify, although they may be broken. However, the problem might be very minimal and a utility for that certain type of file might help.
For example, if you have an AVI file, you can attempt to repair it here, or if you have an MPEG file you can attempt to repair it here, or if you have an MKV file you can attempt to repair it here.
For Usenet users, PAR2 files?
If your RAR file(s) came from Usenet there may be a bunch of .PAR2 files that were posted with it usually with very similar filenames. Download the files and install QuickPar. Run the .PAR2 file after the installation and QuickPar should run automatically. If it does, it will scan over the RAR file(s) and will give you the option to repair if you have enough blocks.
This will only work if you have enough blocks to cover the corrupt blocks. For more information on PAR2 files, read this page.
Hopefully you will have gotten your RAR file repaired either using a recovery record, WinRAR's rebuild or QuickPAR. If not, hopefully you at least got broken files extracted that you may be able to fix with another tool. If you require further help or assistance, please check our Discussion Forums.
Written by: James Delahunty