Cannot extract 7z file - File is broken

2014-05-13
2014-05-16
  • Jason Williams

    Jason Williams - 2014-05-13

    I zipped up a large number of files (over 2000, equaling about 185MB) several years ago into a 7z file. When I try to extract anything from it, I receive "Data error in <filename>. File is broken." for every single file in the 7z file. Not just a couple, every one of them.

    If I open the archive, it appears fine, it shows the original file size, modified date/time, attributes, etc.

    I tried to extract the files using Winrar, and I get a slightly different error. Winrar complains about "Checksum error in <filename>. The file is corrupt."

    I do not have the original files. I stupidly deleted them shortly after creating the 7z file, without testing the archive first.

    Is there any way to recover these files? Is there a way to force extraction? Have it ignore the checksum?

    One thing I noticed, if it matters, is that there were a few .exe files included in the archive. They extract just fine. Looking at the files in the viewer, the .exe files show a different method and a different block from all of the other files.

    Any help would be greatly appreciated.

    Thanks.

    Jason

     
  • thexfile

    thexfile - 2014-05-13

    Could be your virus scanner stopping the process or corrupting the file.

     
    Last edit: thexfile 2014-05-13
  • Igor Pavlov

    Igor Pavlov - 2014-05-14

    Call from command line:
    7z l a.7z > list.txt
    7z t a.7z > test.txt

    And post first lines (lines before error) of both files here.

     
  • Jason Williams

    Jason Williams - 2014-05-14

    7-Zip 9.20 Copyright (c) 1999-2010 Igor Pavlov 2010-11-18

    Listing archive: Kaplan.7z

    --
    Path = Kaplan.7z
    Type = 7z
    Method = LZMA BCJ
    Solid = +
    Blocks = 2
    Physical Size = 81215234
    Headers Size = 44738


    7-Zip 9.20 Copyright (c) 1999-2010 Igor Pavlov 2010-11-18

    Processing archive: Kaplan.7z


    All files have a Data Error in the test output, with the exception of a few .exe files that are in there.

     
  • Igor Pavlov

    Igor Pavlov - 2014-05-15

    Please show more lines of
    list.txt
    test.txt

     
  • Jason Williams

    Jason Williams - 2014-05-15

    7-Zip 9.20 Copyright (c) 1999-2010 Igor Pavlov 2010-11-18

    Listing archive: Kaplan.7z

    --
    Path = Kaplan.7z
    Type = 7z
    Method = LZMA BCJ
    Solid = +
    Blocks = 2
    Physical Size = 81215234
    Headers Size = 44738

    Date Time Attr Size Compressed Name


    2006-02-20 17:14:38 ....A 15523 81164506 Kaplan\Completed Classes\Structured Query Language\Final Project\Final Project.zip
    2006-01-08 17:12:46 ....A 22012 Kaplan\Completed Classes\Structured Query Language\How to Install MySQL.zip
    2006-01-08 17:12:54 ....A 21798 Kaplan\Completed Classes\Structured Query Language\How to Install SQL Express.zip
    2004-01-26 19:27:14 ....A 2260352 Kaplan\Completed Classes\Intro to Web\HTML Student Files.zip
    2004-05-25 11:58:58 ....A 10636 Kaplan\Completed Classes\Intro to DB\Lesson 7\Project 2\Jason Williams Lesson 7 Project 2.zip
    2004-03-18 23:00:11 ....A 299941 Kaplan\Completed Classes\Intro to IT\Lesson 8\Jason Williams Lesson 8.zip
    2004-03-04 09:48:02 ....A 45554 Kaplan\Completed Classes\Intro to IT\Lesson 6\Jason Williams Project 6.zip
    2004-02-18 20:14:00 ....A 84960 Kaplan\Completed Classes\Intro to IT\Lesson 7\Jason Williams Project 7.zip
    2004-12-02 11:43:24 ....A 38649 Kaplan\Completed Classes\Intro to Programming\Final\Jason_Williams_Final_Project.zip
    2004-11-08 09:36:56 ....A 25867 Kaplan\Completed Classes\Intro to Programming\Lesson 5\Jason_Williams_Lesson5_Project.zip
    2005-08-25 15:03:47 ....A 881303 Kaplan\Completed Classes\Technology Infrastructure\Lesson 5\Jason_Williams_Lesson5_Project2.zip

    ...

    2010-08-05 16:02:34 D.... 0 0 Kaplan\Completed Classes\Accounting I\Lesson 6
    2010-08-05 16:02:34 D.... 0 0 Kaplan\Completed Classes\Accounting I\Lesson 5
    2010-08-05 16:02:34 D.... 0 0 Kaplan\Completed Classes\Accounting I\Lesson 4
    2010-08-05 16:02:33 D.... 0 0 Kaplan\Completed Classes\Accounting I\Lesson 3
    2010-08-05 16:02:33 D.... 0 0 Kaplan\Completed Classes\Accounting I\Lesson 2
    2010-08-05 16:02:33 D.... 0 0 Kaplan\Completed Classes\Accounting I\Lesson 1
    2007-08-12 16:23:50 D.... 0 0 Kaplan\Completed Classes\Accounting I\Final
    2010-08-05 16:02:34 D.... 0 0 Kaplan\Completed Classes\Accounting I
    2010-08-05 16:03:25 D.... 0 0 Kaplan\Completed Classes
    2010-08-05 16:03:26 D.... 0 0 Kaplan


                             190410053     81170496  2223 files, 442 folders
    

    7-Zip 9.20 Copyright (c) 1999-2010 Igor Pavlov 2010-11-18

    Processing archive: Kaplan.7z

    Testing Kaplan\Completed Classes\Structured Query Language\Final Project\Final Project.zip Data Error
    Testing Kaplan\Completed Classes\Structured Query Language\How to Install MySQL.zip Data Error
    Testing Kaplan\Completed Classes\Structured Query Language\How to Install SQL Express.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Web\HTML Student Files.zip Data Error
    Testing Kaplan\Completed Classes\Intro to DB\Lesson 7\Project 2\Jason Williams Lesson 7 Project 2.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 8\Jason Williams Lesson 8.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 6\Jason Williams Project 6.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 7\Jason Williams Project 7.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Final\Jason_Williams_Final_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 5\Jason_Williams_Lesson5_Project.zip Data Error
    Testing Kaplan\Completed Classes\Technology Infrastructure\Lesson 5\Jason_Williams_Lesson5_Project2.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 6\Jason_Williams_Lesson6_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 7\Jason_Williams_Lesson7_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 8\Jason_Williams_Lesson8_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 2\Jason_Williams_Lesson_2_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 3\Jason_Williams_Lesson_3_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\MidTerm\Jason_Williams_Midterm_Project.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 3\jason_williams_project3.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 4\Jason_Williams_Project4.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Programming\Lesson 4\Jason_Williams_Project_4.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 4\Less4 Wkly Proj Files.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Web\Lesson 1\Lesson 1.zip Data Error
    Testing Kaplan\Completed Classes\Intro to IT\Lesson 2\Lesson 2.zip Data Error
    Testing Kaplan\Completed Classes\Intro to Web\Lesson 2\Lesson 2.zip Data Error

    ...

    Testing Kaplan\Completed Classes\Advanced Career Development Strategies\Unit 3\Reading
    Testing Kaplan\Completed Classes\Advanced Career Development Strategies\Unit 3
    Testing Kaplan\Completed Classes\Advanced Career Development Strategies\Unit 2\Reading
    Testing Kaplan\Completed Classes\Advanced Career Development Strategies\Unit 2
    Testing Kaplan\Completed Classes\Advanced Career Development Strategies\Unit 10
    Testing Kaplan\Completed Classes\Advanced Career Development Strategies\Unit 1
    Testing Kaplan\Completed Classes\Advanced Career Development Strategies
    Testing Kaplan\Completed Classes\Accounting I\Lesson 8
    Testing Kaplan\Completed Classes\Accounting I\Lesson 7
    Testing Kaplan\Completed Classes\Accounting I\Lesson 6
    Testing Kaplan\Completed Classes\Accounting I\Lesson 5
    Testing Kaplan\Completed Classes\Accounting I\Lesson 4
    Testing Kaplan\Completed Classes\Accounting I\Lesson 3
    Testing Kaplan\Completed Classes\Accounting I\Lesson 2
    Testing Kaplan\Completed Classes\Accounting I\Lesson 1
    Testing Kaplan\Completed Classes\Accounting I\Final
    Testing Kaplan\Completed Classes\Accounting I
    Testing Kaplan\Completed Classes
    Testing Kaplan

    Sub items Errors: 2215

     
  • Igor Pavlov

    Igor Pavlov - 2014-05-16

    Probably there is data corruption in start of archive (first megabyte of data).
    Maybe it's possible to recover first zip files (only 1 MB of data), if you recompile 7-Zip with changed source code.
    Probably it's too difficult or impossible to recover most of files.

     
    Last edit: Igor Pavlov 2014-05-16

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