Testing and Repairing Zip Files

Testing a Zip file

This operation tests the integrity of the open Zip file (.zip or .zipx) and then presents a report with the results.

Using the WinZip ® Ribbon Interface

  • To access the test function, open the Unzip tab (the Zip pane must be the active pane).
  • Click the top part of the Diagnostics button to test the Zip file and view a summary report.
  • To receive a more detailed report, click on the bottom half of the Diagnostics button and click Detailed on the dropdown menu.

When the test is complete, the results will display in the View Last Output window. Click the Clipboard Copy button to copy the report into the system clipboard so you can transfer it to a text editor or an email message.

You can press the Esc key on your keyboard at any time during the Test operation to stop the test.

Causes for a bad or corrupt Zip file

The Zip file format, which is open source, has a specific structure defined in the .ZIP Application Note. By definition, the information recorded in the two Zip file headers should be equivalent. In other words, information recorded about a file in the Central directory should match the information recorded about the same file in the Local directory. This information should also be accurate.

Due to the nature of an open source format, it is very possible for you to receive a Zip file where a simple header issue exists. This header issue may be a minor mistake caused by the application or process used to create the Zip file. However innocent the mistake may seem, WinZip will treat all header inconsistencies, inacurate data, and incorrect extensions as possible security risks and report to you that the Zip file is corrupt. You may want to try to repair your Zip file at some point, as some of these matters can be corrected using a Zip file fix routine.

In other cases when the data in a Zip file is damaged, it may not be possible to fix the Zip file and you will not be able to extract all of the files correctly, if at all. Damaged data can affect the entire Zip file, multiple member files, or just one member file.

There are many possible causes for data damage. Among the most common is a transfer error when downloading a Zip file from the internet. Such an error can introduce invalid data into a Zip file. Some other possible causes include exposure of media to excessive temperatures or magnetic fields and mechanical problems with disk drives.

The best solution to the problem of a damaged Zip file is to try to obtain another copy of the file. For example, use your backup copy of the file or get a new copy from the original source. If you obtained the Zip file by downloading it, then downloading it again may solve the problem.

If the damaged Zip file is on a removable disk, the removable disk may be physically damaged, or the data on it may have been corrupted. In these cases, the only completely reliable solution is to use another, undamaged copy of the disk or Zip file. There are, however, two other situations in which it may be possible to recover some files from a removable disk.

  1. The removable disk drive that you are using to unzip the Zip file may be malfunctioning. Try using a different disk drive, if possible.
  2. If the removable disk drive you are using to unzip the Zip file is not the same drive that was used to store the Zip file on the removable disk, and you have access to the original drive, try using this drive to unzip. It is possible that the original drive may be able to read the disk; if so, you can extract your files using this disk drive (and have your removable disk drives checked out - at least one of them may have a mechanical issue). Otherwise, the removable disk itself or the data on it is probably damaged.

Use WinZip to repair your zip file

Zip files are practical archive file containers that enable you to consolidate multiple files and reduce the storage space they occupy on your hard drive or other storage devices. This archiving method is ideal for storing project files that aren't immediately required and simplifying the transfer of files to other team members. However, like any technology, zip files may occasionally malfunction, resulting in errors or data loss.

Why do zip files need repairs?

There are few things more irritating than trying to access a zip file and discovering it is corrupted. Maybe something in the transfer process didn’t work quite right. Maybe the hard drive it was sitting on was bumped or overheated. Either way, sometimes accessing a zip file reveals an error message telling you it is corrupted or broken. And it’s usually at the time you need it the most.

Fortunately, there is a solution, and it involves WinZip, an all-in-one file management software.

Resolution

1. Make sure WinZip Command Line is installed on your PC.

2. Right-click on the Start button.

3. Open Command Prompt(Run as Administrator).

4. Change directories to the folder where the corrupted Zip file is located, e.g., the one below.

!Testing and Repairing Zip Files - 图1

5. Enter the string of letters and press Enter : "C:\Program Files\WinZip\wzzip" -yf zipfile.zip, where zipfile.zip is the name of the file that needs to be repair.

The repaired file will be located on the source folder and FIXED will be added to its name. Testing and Repairing Zip Files - 图2

Upon execution, WinZip will initiate the repair process of the corrupted zip file, allowing you to access the previously inaccessible files. Once the repair process is completed, you can easily open and retrieve the required files from within the zip archive, enabling you to resume work on your project without any further delay or interruption.

Compiled from the official WinZip Knowledge Base (https://kb.winzip.com/)