When unpacking some ZIP files using Extract All in Vista Home Premium 32bit,
I have found that some of the extracted files are corrupt.

I can drag the individual file out of the ZIP, so the problem is not that
ZIP is corrupt. A Vista machine with WinZip installed will unpack the files
OK.



Looking at a corrupted file, the first 2MB exactly are OK, but the remainder
is filled with zero bytes.

From trying different combinations, it seems that for the corruption to
occur,
- the zip must be password protected
- the original file must be large ( much larger than 2MB)
- the original file must be inside a folder in the zip

The simplest example I have created consists of a single folder containing a
single 14MB text file. The folder is zipped with WinZip on another machine,
using ZIP 2.0 compatible encryption. This file has has been tested on a
couple of Vista machines and the corruption occurred on both.

Yeah I've had the corrupted zips problem, and I'm using home premium. It
doesn't always happen on extracting either, it also happens when creating big
zip files. I use 7zip now to extract the zips and I only create 7z archives
now. Much better than Vista's zip program.

"Martin" wrote:

> When unpacking some ZIP files using Extract All in Vista Home Premium 32bit,
> I have found that some of the extracted files are corrupt.
>
> I can drag the individual file out of the ZIP, so the problem is not that
> ZIP is corrupt. A Vista machine with WinZip installed will unpack the files
> OK.
>
> Looking at a corrupted file, the first 2MB exactly are OK, but the remainder
> is filled with zero bytes.
>
> From trying different combinations, it seems that for the corruption to
> occur,
> - the zip must be password protected
> - the original file must be large ( much larger than 2MB)
> - the original file must be inside a folder in the zip
>
> The simplest example I have created consists of a single folder containing a
> single 14MB text file. The folder is zipped with WinZip on another machine,
> using ZIP 2.0 compatible encryption. This file has has been tested on a
> couple of Vista machines and the corruption occurred on both.
>

Thanks for the confirmation.

I don't really want to tell people to install software when I send them a
ZIP, especially considering the number of posts from people having problems
with the ZIP file association.

"Necunoscut" wrote:

> Yeah I've had the corrupted zips problem, and I'm using home premium. It
> doesn't always happen on extracting either, it also happens when creating big
> zip files. I use 7zip now to extract the zips and I only create 7z archives
> now. Much better than Vista's zip program.
>
> "Martin" wrote:
>
> > When unpacking some ZIP files using Extract All in Vista Home Premium 32bit,
> > I have found that some of the extracted files are corrupt.
> >
> > I can drag the individual file out of the ZIP, so the problem is not that
> > ZIP is corrupt. A Vista machine with WinZip installed will unpack the files
> > OK.
> >
> > Looking at a corrupted file, the first 2MB exactly are OK, but the remainder
> > is filled with zero bytes.
> >
> > From trying different combinations, it seems that for the corruption to
> > occur,
> > - the zip must be password protected
> > - the original file must be large ( much larger than 2MB)
> > - the original file must be inside a folder in the zip
> >
> > The simplest example I have created consists of a single folder containing a
> > single 14MB text file. The folder is zipped with WinZip on another machine,
> > using ZIP 2.0 compatible encryption. This file has has been tested on a
> > couple of Vista machines and the corruption occurred on both.
> >