Solution to File Corruption due to WinRAR CRC verification failure

I downloaded a software program of nearly one GB yesterday. When I decompressed the package, I was prompted that "CRC verification failed and the file was damaged". It would take more than four hours to download the software again, I have tried many methods on the Internet, but they are not easy to use...
The method I used is simple: copy the file to another directory without decompression (when an error is prompted). After decompression is completed, OK and the file is still easy to use, this method should be targeted or enumerate the network practices.
Network Method:
Method 1: WinRAR has the compressed package repair function. Click "Fix compressed files" under "Tools". The shortcut key is "Alt + R ". This method can fix Common Errors of some compressed packages, but the success rate is not high. You can try to fix it several times in a row. This function of WinRAR is suitable for scenarios where many files in the compressed package and the file capacity is relatively small.
Method 2: Open the compressed package (rather than decompressing it with WinRAR), select the file you want to decompress, right-click the file, and select "directly decompress without confirmation" in the pop-up menu ", the shortcut key is "Alt + W ". With this method, both good and bad compressed packages are smooth and the success rate is 100%!
Method 3: pay-as-you-go!

The principle is to decompress corrupted files in the RAR Archive without the WinRAR warning. The decompression software still uses WinRAR, but a small setting is required.

Right-click the decompressed file and select the "retain damaged file" check box and click "OK" to start decompressing the file. Ignore the information about the decompression error. After decompression, you will find that the damaged file has been decompressed. The probability of normal use of damaged files decompressed in this way is very high.

Do a good job in insurance
1. Make recovery records
When the original RAR compressed package is compressed, if you choose to place the recovery record, the user will have the chance to fix the CRC error even after the download!

2. volume-based compression
Using the volume compression method can greatly reduce the loss caused by unrecoverable errors.

3. Add recovery records to old files
Someone may ask, the newly compressed RAR package can be added with the recovery record. Is there any way to add the recovery record to the compressed RAR package? There is a way to add recovery records to the compressed RAR compressed package.

You only need to open the compressed file, and select "protect file" in the "command" menu.

 
TIPS:
In fact, the main solution to RAR compressed package errors is prevention! If there is no prevention, there will be no technical solution when a real problem arises! In the case of a cyclic redundancy checksum (CRC) error, if the RAR compressed package does not contain a recovery record, it is impossible for the user to fix the CRC himself! The main purpose of this article is to tell you the cause of the error and discuss some ways to fundamentally prevent the error and minimize the loss!

Appendix:
1. CRC Algorithm Principle
CRC is short for Cyclic Redundancy Code. It is translated into Chinese as "cyclic escape Code". It adopts polynomial encoding method and is an efficient error control method. CRC32 is the 32-bit CRC algorithm, which is the algorithm used by SFV. The CRC algorithm has simple encoding and decoding methods and strong error checking and Error Correction capabilities. Therefore, it is widely used in communication, satellite, control, and other fields. In our computer, it is also widely used in compression, disc burning, and data storage.
In fact, when talking about CRC, we are more likely to think about the compression software, because many friends have encountered the "CRC error" prompted by the compression software, which is actually a file verification process, this process is automated: the compression software automatically adds CRC verification information to the package when compressing the file. during decompression, CRC is automatically verified to check whether the file is complete and correct.
Practice: solutions to CRC errors
Symptom 1: Recently, No matter what files are decompressed by WinRAR, the system prompts "CRC verification failed and the file is damaged ".
Solution: In this case, the temporary file storage of WinRAR may be faulty, generally, you only need to open the temporary system directory (\ Documents and Settings \ USERNAME \ Local Settings \ temp in Windows 2000/XP ), delete the folder named "RAR $ di00.
Symptom 2: When a downloaded software package is decompressed using WinRAR, a message is displayed, "CRC verification fails and the file is damaged ".
Solution: in this case, it can be determined that the compressed package has a problem. However, in many cases, the CRC error does not mean that the entire compressed package has been broken, but may be partially damaged. You can try to use "Fix compressed files" in the "command" menu to solve some CRC errors. If it still cannot be solved, you can try the forcible decompression technique: First open the compressed package, select all files except the CRC error file, and first decompress the normal file, decompress the wrong file. When the CRC error message is displayed, do not click the OK button to open "Resource Manager" and find the path to save the extracted file, you can see that the file with the error has been decompressed, copy it to the folder where other files are saved, and then try again. Program In many cases, if this file is not an executable program, it will not have a great impact on the operation.
Simple and Convenient WinRAR user identity verification
In addition to the CRC automatic verification function, WinRAR also provides a special identity verification function to help you know whether your compressed package has been modified.
Practice: Create a compressed package that can only be used but cannot be changed

In "Resource Manager", select the file to be compressed, right-click it, and select "add to compressed file" to open the "compressed file name and Parameters" window, select the "Add User identity verification information" option in "compression options" and click "OK" to generate the compressed package.

Double-click to open the package. You can see the "user verification information exists" prompt in the address bar. Click "command> display information" to open the dialog box, in the "user identity verification information" column, you can view the file name, creator, and creation date of the compressed package (see figure 1), and write down the information, especially the information in the "creator.

Now you can provide the compressed package to the receiver and user identity verification information. When the other party opens the compressed package, it can open the "display information" dialog box and compare it with the identity verification information you provide. If the same, it indicates that the compressed package has not been modified, if the authentication information does not exist or has changed, it indicates that the package has been modified.
Tips
This function requires WinRAR of the registration version, because the authentication information is generated based on the registered user name. When a compressed package with the identity verification information added is modified, the authentication information is lost, this is the Verification Principle.

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Author: winzheng
Source: http://cnblogs.com/winzheng
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