Extract from an Incomplete 7zip file

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Anonymous
2012-06-09
2012-12-07
  • Anonymous - 2012-06-09

    I recently created a 7zip archive containing a backup of pictures which I then copied to a usb thumbdrive and reformatted the computer, however when I went to unpack the archive I got an error saying that the file cannot be opened as an archive. I think I may have unplugged the usb drive before the backup was complete as I think it was 2.xgb before and the current file is only 1.9gb. I'd really like to recover as much of that data as possible, I've seen similar requests asking for the first 32 bytes and the last 64 bytes of the archive

    First 32 bytes
    FF D8 FF E0 00 10 4A 46 49 46 00 01 02 00 00 01
    00 01 00 00 FF FE 00 04 2A 00 FF E2 02 1C 49 43
    Last 64 bytes
    98 7C 7F CB 9D 6A 92 6D F3 21 F1 19 B1 AE 30 D5
    F8 85 A4 4D 15 70 F7 A5 24 82 AD 49 E5 F9 BA 99
    EB CA 6A 08 1D BB 24 5C 75 8E DE 72 9D FF D1 52
    8A 3B A1 FB 86 D8 EA 93 9A DA B5 E3 27 32 FE 44
    

    although if it's only a partial file I'm hoping to be able to manually create the ending.

    Thanks. And I will definitely be testing my archives next time :/

     
  • fernando

    fernando - 2012-06-09

    thumbdrive is formated NTFS, not some FATxx?

     
  • Anonymous - 2012-06-10

    it's FAT32

     
  • Anonymous - 2012-06-10

    er the thumbdrive is FAT32, but the bytes I gave above are after writing it to the local NTFS file system. So I guess NTFS is what you wanted to know? Or should I read the bytes directly off the file on the thumbdrive?

     
  • Igor Pavlov

    Igor Pavlov - 2012-06-10

    That file looks like jpeg file.
    Try to rename it to jpeg and open.
    Check another files in your thumbdrive. Maybe some another file is 7z archive.

     
  • Anonymous - 2012-06-11

    A 1.9gb jpeg file? I'm positive it is the .7z archive, I didn't put the extension there by hand. However as I stated I may have pulled the thumb drive out early causing the file to be incomplete. Is it the end headers that make you think it may be a jpeg? Does that mean the headers are intact and I can search through and extract the images?

     
  • fernando

    fernando - 2012-06-12

    The 'first 32 bytes' you posted has JFIF (JPEG File Interchange Format) marker (see: oi48.tinypic.com/5yg4ux.jpg).
    7-Zip archives have 7z marker.

     

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