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John Paul Cook

Windows and Mac not playing nicely with zip files

I’m having a terrible time with a new Cisco E4200 router and WMP600N dual band wireless network adapter. Cisco directed me to download a zip file of driver files, but they created it on a Mac. Zip files created on a Mac can sometimes unzip on Windows as NTFS encrypted files. Cisco doesn’t believe me, but it’s true nonetheless.

Using the built-in Windows 7 unzip feature, Mac zip files will under still mysterious circumstances unzip on Windows as NTFS encrypted. In other words, they appear as green in Windows Explorer. This doesn’t happen if 7-Zip is used to extract the files. When the files were encrypted, I was not successful installing the driver. Since I have a portable version of 7-Zip on all of my machines, it’s more efficient to extract with 7-Zip than go to the trouble of unencrypting all of the files. It’s not just this particular Cisco zip file that has the problem as others have reported here.

It would be nice if Cisco would not create zip files on a Mac if the files are really intended for Windows users. It creates an unnecessary problem that wastes the customer’s time and is difficult to troubleshoot. As a best practice, I’m not going to create any zip files on a Mac and distribute them to Windows users unless and until I can find a way to prevent this encryption problem.

I’d like to see a few other people try to reproduce this problem. The zip file can be downloaded from here:

I’ve reproduced this problem on three different Windows 7 machines, both x32 and x64. The problem occurs with or without unblocking the downloaded file. If you can reproduce the problem, please report your results by adding a comment.

Published Friday, July 8, 2011 6:38 PM by John Paul Cook

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AaronBertrand said:

I've never seen a ZIP file created on any of my Macs become encrypted when I tried to open them in Windows, and I've used this method to move files between systems a lot.

July 8, 2011 7:17 PM

DarinStrait said:

I unblocked the zip file (Right click the zip file->Properties, then click the unblock button) and extracted the files. They do show up as encrypted. They appear to be readable. I can drop the netr28 setup information file into a text editor and easily read the contents. I can flag the files as unencrypted by right-clicking the Win7_32 folder, then selecting Properties, clicking the Advanced button and unchecking "Encrypt contents to secure data", then clicking "OK", "Apply" and "OK".

I can't tell if there is any other damage to the files, but they seem usable.

I don't know much about Macs, but perhaps the zip tool they are using has some option that is set (or not set). I am under the impression that old resource fork issue went away when Apple released OSX. The last time I really used Macs was under OS 6 or 7.

July 9, 2011 8:14 AM

AaronBertrand said:

I downloaded the Zip file to Windows 7 x64 and had no problem viewing the contents natively. I do not have any 3rd party zip handlers installed, and I did nothing but click on your link, save the file, and open it.

PS my point is not to suggest that this isn't happening to you, but rather that you are blaming an entire platform for something that is different either about the way Cisco is packaging these files or the way your system is interpreting them. The fact that you and I get different results from the same file leads me to believe this is a local issue, not a global one.

July 9, 2011 8:20 AM

AaronBertrand said:

I had never tried the Unblock button before... have never *needed* to do that to use the zip file (including in this case). When I extract the archive after unblocking it, yes the files show as encrypted, but they're still usable as far as I can tell.

Anyway, I can get the files out of the given zip file without them ever showing up as encrypted... just double-click the copy instead of using the Extract All functionality. In fact maybe it's something wrong with Windows' Extract functionality, as opposed to the way the Mac creates the zip?

July 9, 2011 8:32 AM

John Paul Cook said:

I'm not blaming the Mac platform. As I stated, I would like Cisco to stop packaging files this way. It appears to be a bug in Windows - after all, 7-Zip works just fine. But considering that the behavior is known now, it is easier to prevent the problem than patch Windows. As a best practice, I'm not going to zip files on a Mac that will be distributed to Windows users.

July 9, 2011 9:42 AM

Gene said:

I downloaded the file and with WinZip it unzip normally.  However if I used Explorer to unzip the file the files were encrypted.  I have never seen this before.

July 9, 2011 6:30 PM

ronald said:

I can confirm this is a bug in windows 7 / explorer standard zip.

files are zipped on a mac, unpacked on windows 7 with standard explorer zip.

The folders come out green and encrypted.

copying files to a network share makes deleting or anything else impossible.

taking ownership or changing tights does not work

Also mentions teh same problem.

February 7, 2012 7:11 AM

ronald said:

After changing tights, changing file/folder rights does not work also.. ;)

February 7, 2012 7:13 AM

Roger said:

Here is a posting that gives more of the why, unfortunately no fix other than to manually unencrypt them. Right click; Properties; Advanced; Uncheck Encrypt)

September 24, 2012 2:15 PM

John Paul Cook said:

It is fixed in Windows 8. I reported as a bug in the spring and provided additional information that Microsoft requested. I confirmed that the bug is fixed in Windows 8 RTM.

September 24, 2012 2:42 PM

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About John Paul Cook

John Paul Cook is a database and Azure specialist in Houston. He previously worked as a Data Platform Solution Architect in Microsoft's Houston office. Prior to joining Microsoft, he was a SQL Server MVP. He is experienced in SQL Server and Oracle database application design, development, and implementation. He has spoken at many conferences including Microsoft TechEd and the SQL PASS Summit. He has worked in oil and gas, financial, manufacturing, and healthcare industries. John is also a Registered Nurse currently studying to be a psychiatric nurse practitioner. Contributing author to SQL Server MVP Deep Dives and SQL Server MVP Deep Dives Volume 2. Connect on LinkedIn

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