.zip files from Mac OS show up as green/encrypted

Green files and folders on Windows 7 indicate they are encrypted.

Usually this is a function of a program that will make these files encrypted for a reason. Security is usually the reason. But…

An interesting little bug in the process of creating a .zip file on a mac and moving it over to a Windows computer.

When a .zip file is created according to standards for .zip files found here:

http://www.pkware.com/documents/casestudies/APPNOTE.TXT

They specify that .zip archives include a tag informing about itself to the program trying to decompress the archive. This tag information is known as the “version made by” and as the name suggest, it would tag information about the program version of .zip and the files system in use.

 0 - MS-DOS and OS/2 (FAT / VFAT / FAT32 file systems)
          1 - Amiga                     2 - OpenVMS
          3 - UNIX                      4 - VM/CMS
          5 - Atari ST                  6 - OS/2 H.P.F.S.
          7 - Macintosh                 8 - Z-System
          9 - CP/M                     10 - Windows NTFS
         11 - MVS (OS/390 - Z/OS)      12 - VSE
         13 - Acorn Risc               14 - VFAT
         15 - alternate MVS            16 - BeOS
         17 - Tandem                   18 - OS/400
         19 - OS/X (Darwin)            20 thru 255 - unused

When the Mac system encrypts the files, it marks them with the attribute of being UNIX based files. Correct considering the Mac operating system is based on UNIX.

The problem arises at the Windows end. Because Windows is created by the most arrogant computer company in the world, it does not recognise that a .zip file could have been created with a computer that is not running Windows. It fails to correctly see the flag as UNIX and marks the files as Encrypted.

Leaving Files Encrypted

If the files are left as encrypted, you may find that there are problems if the files are shred on a network drive etc. Taking ownership will not change this flag, and resetting permissions does nothing.

The Easy Fix – Remove Encrypted Tag

Removing the incorrect Encrypted Flag on a green file in Windows 7, or Windows Server is really easy. Right click the file or files (holding the shift key to select multiple folders and files) then Click: Properties / Advanced / Un-tick the Encrypted Option

 

That’s about it. All fixed.

3 Replies to “.zip files from Mac OS show up as green/encrypted”

  1. Not so fast! My Windows 7 still doesn’t like the green file from my Macbook. When I apply the ‘encrypted (Unix) bit’ change, Win7 complains that an error occurred and denies me access. But it recognizes that I am the file owner and have full permissions. I can’t email the file to my Linux machine, I can’t open it in an app, … Feh, hope this is a corrupted file or something, it is exhausting trying to wrestle it open.

  2. This works only if you are the owner of the files and folders in question.
    Ownership cannot be changed.
    If the SID does not match there is literally nothing that can be done short of formatting the drive to get rid of them.
    The owner must login to make the change and LSASS must not have the file locked open.

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