Files with 0kb



  • I have an evaluation copy of PawerArchiver. I have some .zip files with compressed .xls files within. When I extract them, they appear to uncompress, but the resulting files have no data and no size (0kb).

    When I try Winzip or WinRAR, they say that the compression method is unknown. I have had the same problem with several files recently. All have been emailed to me by different people.

    Any help appreciated.



  • Welcome to PowerArchiver forums!

    Thank you for evaluating PowerArchiver.

    it seems that those zip archives are corrupted. This can happen if archive is delivered via e-mail. What is the size of .zip file?
    also, it may be encrypted with some unsupported algorithm.
    try redownloading it.

    thanks,

    Serhiy



  • Thanks Serhiy.

    The files range in size from a few hundred KB to 10MB. I have tried downloading the file from the email, with no luck. I will try talking to my ISP.



  • in some cases PowerArchiver Repair feature may help. You are welcome to try…



  • Another possibility is that they were created using WinZip 11 - and so not actually using the ZIP format, but ppmd ….
    I think only WinZip can unpack those at the moment …



  • Thanks TBGBe,

    This is exactly right. I downloaded an evaluation of WinZip 11 and this solved the problem.



  • @TBGBe:

    Another possibility is that they were created using WinZip 11 - and so not actually using the ZIP format, but ppmd ….
    I think only WinZip can unpack those at the moment …

    Cripes! You mean that the zip file specification does not contain information an unpacker can use to figure out that it cannot handle the format so it can tell the user a nice informative message?


  • conexware

    @mwb1100:

    Cripes! You mean that the zip file specification does not contain information an unpacker can use to figure out that it cannot handle the format so it can tell the user a nice informative message?

    you mean Cripes! 2 companies are extending format on their own and now ZIP can mean anything… Currently “specification” has deflate, deflate64, ppmd (1,2), bz2 (1,2), lzma, and 2 different AES implementations.

    So seeing an “zip” format, really does not mean much anymore. I can understand addition of AES, but everything else is just tacked on to make it different.

    It is annoying me greatly but of course, two can play the game <evil grin="" inserted="">.</evil>



  • @spwolf:

    you mean Cripes! 2 companies are extending format on their own and now ZIP can mean anything… Currently “specification” has deflate, deflate64, ppmd (1,2), bz2 (1,2), lzma, and 2 different AES implementations.

    I know nothing about the zip specification - I just figured that there would be some algorithm ID or signature field in the zip header that would let programs know what they should use to decompress the contained file. And if the signature was unknown to a program, it could indicate that to the user in an error message.

    If that doesn’t exist or is unreliable, then certainly there’s not much that PA can do about it. But it’s still a little disappointing, especially as the zip format has been extended more than once so you’d think that this issue might have been given some thought by whoever was doing the extending.


  • conexware

    @mwb1100:

    I know nothing about the zip specification - I just figured that there would be some algorithm ID or signature field in the zip header that would let programs know what they should use to decompress the contained file. And if the signature was unknown to a program, it could indicate that to the user in an error message.

    If that doesn’t exist or is unreliable, then certainly there’s not much that PA can do about it. But it’s still a little disappointing, especially as the zip format has been extended more than once so you’d think that this issue might have been given some thought by whoever was doing the extending.

    well problem is that you need to program extensions if you want them to be recognized.

    and then what to say - for instance, would someone at WinZip write “download latest PowerArchiver to view this file”?

    It is not an simple question, I just dont like how zip today has nothing to do with .zip just 2 years ago.

    Imagine an outcry if MS called their new office format .doc so all the people with older software would end up confused on why cant they open it…


 

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