Windows – How to create an executable RAR file

Several versions ago, Internet Explorer introduced the concept of "security zones" – Internet, local intranet, "trusted", "restricted". Later, this was extended to the Windows Explorer shell (and a "My Computer" zone was added).

After downloading the file, the browser – both IE and Chrome – adds an "alternate stream" to it, named Zone.Identifier, which says that the file came from the "Internet" zone. When you double-click a file in Windows Explorer, it checks if such a stream is present, and asks for confirmation if necessary. This is not restricted to executables – any file tagged this way will require confirmation.

Alternate streams are a feature of Windows and the NTFS filesystem, and are stored on disk as part of the file. (In NTFS, the actual contents of a file is in fact an unnamed stream too.) If you want to see or edit the contents of Zone.Identifier, run in command line:

notepad MyDownloadedApp.exe:Zone.Identifier

When you uncheck the "Always prompt..." box, or when you click "Unblock" in the file properties window, the Zone.Identifier stream is deleted and Explorer won't require confirmation anymore. To delete all streams from many files at once you can use Streams or a graphical tool.

If you want to disable the zone tagging, refer to this post for Google Chrome.

I'm going to have to disagree with the other answers posted so far. What you're looking to achieve is technically possible with certain caveats. Looking at the RAR archive format, if solid archiving and encryption are not used it is possible to create a new archive with a modified main archive header and only the required file records (file headers, data blocks, service headers etc.) copied over without the data blocks needing to be decompressed first.

The process should be similar to this one for ZIP files, suitably adjusted for the RAR format of course.

Also, I'd like to note that WinRAR already does this to some extent, i.e. if you delete files from a non-solid RAR archive it does not decompress the data in any way, though of course temp files may be used for safety.

So what are your options here?

1. If you don't need the 50k files you can delete them directly from the source archive. If solid archiving wasn't used no decompression and recompression will be required.

2. If you might need some of the files later you can copy the source archive and then follow option 1.

3. Of course you can always extract and recompress only the required files as a new archive.

4. Finally, like I said above if solid archiving wasn't used a new archive with only the required files can be created without decompression. However, since this is such an uncommon requirement I'm pretty sure no program already exists that can do this, so you'll have to write one yourself or wait till someone does so.

_{Note: Answer was posted after receiving confirmation from the WinRAR developer that the technical analysis was sound.}