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Yet another 7z corrupted file

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2014-04-27
2014-04-29
  • Anass Mouhsine
    Anass Mouhsine
    2014-04-27

    Hi all!
    First of all, I would like to take the chance to thank Igor for 7zip that I used for a long long time.
    Here is my problem: my hdd is dead and I thought I had a copy of my most valuable files in 7z format.
    Two files bad1.7z and bad2.7z that I cannot open as archive.

    I have read most of the threads here to find a solution for my problem, but did not find an easy way.
    (Well I don't know how to split the files as done in this thread http://sourceforge.net/p/sevenzip/discussion/45798/thread/e34b4a1d/ )
    Here are the details for both files:

    1) bad1.7z (includes folders and files (mainly .cs & .dll) )
    size: 243 269 632 bytes
    first bytes in hex
    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 18 E0 E4 64 3A 4E 7E A2 68 BD 69 41 81 2B 7F

    last bytes in hex
    04 23 0A E5 6C 6A 1F CA AD 28 0B 1D 2E B3 91 69
    B7 86 FD A4 00 F9 1E E1 4D 73 2F EA 23 06 3B C5
    5E 48 B5 3F 02 D4 70 62 B0 38 87 E8 24 CA 28 86
    

    2) bad2.7Z (includes folders and files (mainly *.r) )
    size: 4 934 598 656 bytes
    first bytes in hex
    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 3D 82 8C 2C 6D A3 28 99 32 58 4C 77 22 A8 1B

    last bytes in hex
    93 BA 89 83 C7 A2 33 73 F0 18 56 38 E4 DC F6 88
    64 B6 17 F6 45 F3 EF 17 1E F6 B0 6D 9F 62 62 8C
    4A D1 1D 4D 65 F4 6A 02 17 E8 84 BC 9F 26 65 F3
    

    Is it possible to recover some of the files in bad1.7z and bad2.7z?

    Thank you in advance for your precious help.
    Anass

     
  • Igor Pavlov
    Igor Pavlov
    2014-04-28

    Archive creation was interrupted in both cases.
    So there is no header at the end (file names and file sizes and so on).
    You can recover raw data stream at start of archive.
    Read another threads about recover procedure.
    It's simpler to work with small archive at first.

     
  • Anass Mouhsine
    Anass Mouhsine
    2014-04-28

    Thank you Igor for your prompt answer.
    I've already done as instructed in the threads and I have access to the first files in the 7z file without info on names nor sizes as you said.(unfortunately for me)
    I am still in the process of recovering what I can.

    Is there a way to know what is the cause for the archive interruption? The fact that this happened to the two files is suspicious.

     
  • Igor Pavlov
    Igor Pavlov
    2014-04-29

    I don't know about reasons of interruption.

    Some additional notes:
    1) And you can try to use parser mode in 7-zip 9.32 alpha to extract files from raw file.
    2) If archive is big, maybe you have several solid blocks. So to recover it, you need to find start of solid block (start of another LZMA stream). It can be pretty difficult, but it's possible.
    First byte in LZMA stream is 0 and high bit in second byte in LZMA stream is 0 also.