How to Fix a Headers Error in a 7z Archive
Step 1: Open the Corrupted Archive in a Hex Editor
- Download a Hex Editor: If you don’t have one, download a hex editor like FAR Manager or HxD.
- Open the Corrupted Archive: Launch the hex editor and open the corrupted 7z file.
Step 2: Check the Start Header
- Locate the Start Header: The Start Header is the first 32 bytes of the file.
- Verify the Signature: The first 6 bytes should be:
37 7A BC AF 27 1C
If these bytes are not correct, the Start Header is likely corrupted.
Step 3: Repair the Start Header
- Replace the Start Header: If the Start Header is corrupted, replace the first 32 bytes with the following values:
37 7A BC AF 27 1C 00 04 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
- Save Changes: After making the changes, save the file in the hex editor.
Step 4: Check the End Header
- Locate the End Header: Scroll to the end of the file to find the End Header.
- Verify the End Header: The End Header should contain a link to the Metadata Block. If it’s missing or corrupted, you may need to create a new End Header.
Step 5: Calculate the Correct Size
- Calculate the Total Size: Use the values from the Start Header to calculate the correct size of the archive.
- The size can be calculated as:
Correct Size = Size of Compressed Data + Size of Metadata Block + Size of End Header
- Adjust the Archive Size: If the total size is incorrect, you may need to add or remove data to match the calculated size.
Step 6: Test the Archive
- Open the Archive in 7-Zip: After making the changes, try to open the archive in 7-Zip.
- Test the Archive: Use the "Test" command in 7-Zip to check if the archive can be opened without errors.
Step 7: Extract Files
- If the archive opens successfully, try to extract the files. If you encounter any errors during extraction, refer to the previous steps to troubleshoot further.
Additional Tips
- Backup the Original File: Always make a backup of the original corrupted file before making any changes.
- Use a Reliable Hex Editor: Ensure you are using a reliable hex editor to avoid accidental data loss.
By following these steps, you should be able to fix a Headers Error in your 7z archive. If you continue to experience issues, it may be necessary to seek additional recovery tools or professional help.