Winzip

[Tosh McCaber]

I sent a package, zipped using Winzip 14. The recipient couldn't open it. I was then told by my local computer guru that the Winzip programme is incompatible with the native zip package built into Windows (I didn't even know that Windows had an inbuilt zip programme to zip and unzip files, without the need for Winzip).

Can anyone clear my mind on all this?

[bnt]

Looks like something changed with WinZip 10 (and, I presume, later versions): Error message when you extract a compressed file that has a .zip file name extension on a Windows Vista-based computer: "This file was compressed using an unknown compression method" (http://support.microsoft.com/kb/938319)

WinZip 10 uses a compression method that is incompatible with some versions of Windows and with earlier versions of WinZip.
...
To work around this problem, select the Maximum (portable) compression method in WinZip 10.
...

You might be able to extract it with 7-Zip Portable (http://portableapps.com/apps/utilities/7-zip_portable) (which needs no admin rights to install and use)

[ab33t]

Another solution is to download winrar , this program covers most compressed formats

[Bushfiva]

Winrar, like Winzip, is not free. I realise this doesn't worry many people here. 7-zip is, however, a free solution.

[seacue]

I have discovered that Win XP's internal unZIP redates files to the time they are unZIPped. This causes misleading info in software I have written.

7-ZIP, PKUNZIP and WINZIP maintain the date in the ZIP file.

[Tosh McCaber]

My question really was- can I be sure that a file sent, say with Winzip, or a similar proprietary zip package, will be able to be opened with a computer with only the native zip package built into Windows, and vice versa?

[Bushfiva]

Choose "zip legacy" or whatever the option's called today. Don't allow "optimize for best compression".

[Gertrude the Wombat]

My question really was- can I be sure that a file sent, say with Winzip, or a similar proprietary zip package, will be able to be opened with a computer with only the native zip package built into Windows, and vice versa?
No, you can't.

My solution is to keep a copy of Winzip on every machine I use and ignore the non-working built-in "feature".

[bnt]

I thought the Microsoft article answered that question: use the "Maximum (portable)" option, or "legacy" if WinZip 14 calls it that.

[Gertrude the Wombat]

What usually happens is

- you receive a zip file from somewhere
- you didn't make it, you have no idea how it was made
- you access it using Windows and it appears to work
- however eventually, on a really bad day this'll be after a couple of hours wasted work, you realise that there are some files missing
- you access it again using Winzip this time and everything is fine.

The only safe thing to do is use Winzip to read incoming zip files. Of course if you're in control of the entire process you can do what you like, but the usual use of zip files is receiving them from someone else.