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Error: Can not open file as archive

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2013-03-07
2013-11-27
  • Hi,

    i've got a problem extracting an archive generated with 7z. The archive was created with 7-Zip 4.65. The command used to create the archive was : "7z.exe a archiv.7z textfile.log"
    There is only 1 file in the archive and the content of the file is only ascii text.

    Size of the 7z file looks good (i've got several other files with almost the same contents, the same filename inside the archive, only the contents of the file differ).
    I'm assuming that only some part of the archiv's header got damaged.

    Is there any way to recover the file from the archive?
    I could provide a working example and the not working archive.
    Would be awesome if someone could give me a hint on howto recover the data.

    I saw Roblad has / had a similar problem over here: https://sourceforge.net/p/sevenzip/discussion/45797/thread/c6a35f22/
    But i don't know how to provide this information and what to do with the information.

    Cheers
    Chris

     
  • Igor Pavlov
    Igor Pavlov
    2013-03-07

    Show
    1) exact size of archive.
    2) first 48 bytes in hex.
    3) last 64 bytes in hex.

     
  • OK here you go:

    Name of compressed file: comport1.log
    Exact filesize: 655392 Bytes (Windows Explorer)
    first 48 Byte:
    37 7A BC AF 27 1C 00 03 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 19 0C 02 6C 18 7F 92 69 C5 B9 BC E9 1F F5 CD

    last 64 Byte:
    AE BB 57 14 9A F3 06 E3 1B 7B 19 11 79 25 71 E2 04 AF B0 D5 A2 20 9E 76 BA 4C 22 47 25 AB DF B4 BE E5 FA 52 1E CF 47 CC C0 30 16 27 FE 95 34 B5 B6 D4 38 F5 A0 91 16 CE DB E7 32 A2 88 0A 5F 1F

    The data from a working file (as described above) is:
    Name of compressed file: comport1.log
    Exakt filesize: 101414 Bytes (Windows Explorer)
    first 48 Byte:
    37 7A BC AF 27 1C 00 03 09 D7 F9 D2 AA 8B 01 00 00 00 00 00 5C 00 00 00 00 00 00 00 1B 77 AA 46 00 19 0C 02 6C 18 7F 92 69 C5 B9 BC E8 5E 44 56

    last 64 Byte:
    99 00 08 0A 01 E0 8F 12 32 00 00 05 01 11 1B 00 63 00 6F 00 6D 00 70 00 6F 00 72 00 74 00 31 00 2E 00 6C 00 6F 00 67 00 00 00 14 0A 01 00 7B DC 0B 52 CE 19 CE 01 15 06 01 00 20 00 00 00 00 00

    thanks for your help!

     
    Last edit: Christoph Vollmer 2013-03-07
  • Igor Pavlov
    Igor Pavlov
    2013-03-08

    Archive creating was not finished.

    1) split bad.7z
    to
    - bad.7z.001 - 32 bytes
    - bad.7z.002 - remainder. (655392 - 32 bytes) in your case
    2) create a.7z that is at least 1 MB larger than bad.7z.
    3) split a.7z to
    - a.7z.001 - 32 bytes
    - a.7z.002 - (655392 - 32 bytes)
    - a.7z.003 - remainder
    4) delete a.7z.002 and rename bad.7z.002 to a.7z.002.
    5) try to extract from a.7z.001.

     
  • Hi,

    this did work.
    Thank you very much!
    Some of the data was lost but this is nor problem at all.

    Thanks again for this great support.

    Chris

     
  • Wagner
    Wagner
    2013-11-16

    Dear Igor,

    I have a similar problem like Christoph. I can't extract a file of 4.605.087.319 bytes (It's the result of a long list of private data). When I try to test the file, I got "it's not possible to open file as archive" information. I just use the GUI, so I don't know how to retrieve the information about the first and last bytes in hex.

    Anyway, I tried to split my bad.7z file and all I got was a 440 files result.
    I have a big problem in hands and I don't know how to solve it. Please, if possible, help me in doing it!

    I appreciate a lot!

    Wagner

     
    • lp010437
      lp010437
      2013-11-27

      sorry

      2013/11/17, Wagner wagnerarruda@users.sf.net:

      Dear Igor,

      I have a similar problem like Christoph. I can't extract a file of
      4.605.087.319 bytes (It's the result of a long list of private data). When I
      try to test the file, I got "it's not possible to open file as archive"
      information. I just use the GUI, so I don't know how to retrieve the
      information about the first and last bytes in hex.

      Anyway, I tried to split my bad.7z file and all I got was a 440 files
      result.
      I have a big problem in hands and I don't know how to solve it. Please, if
      possible, help me in doing it!

      I appreciate a lot!

      Wagner


      Error: Can not open file as
      archive


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