If you’re managing your hard drive, and need to have a group of files accessible from two or more folders, then the solution seems obvious: just make some copies. But while this is quick and easy, it wastes hard drive space, and if you forget about the copies (which you will) they could be cluttering your system for a very long time.

Hard links are an NTFS feature which could offer a better solution. A hard link is essentially an alternate name for a file on an NTFS drive, enabling you to make one or more files appear in as many locations as you need. And as all the references point to the same file, no extra disk space is required at all.

Windows can create hard links natively via the command line (check out fsutil.exe), but that’s not exactly convenient. Install Link Shell Extension (64-bit) and you’ll be able to use hard links – and several other advanced NTFS features – directly from the Explorer right-click menu, just as easily as a copy and paste.

Hard links are created from Explorer’s right-click menu

To take a simple example, suppose we wanted Picture.jpg in folder A to also appear in folders B and C. We would start by right-clicking the file and selecting “Pick Link Source”. Right-clicking folder B and selecting Drop As > Hard Link would create our first link, and we’d just repeat the process in folder C.

The end result is you’ll have what appears to be three copies of Picture.jpg. They’ll be previewed as normal, and you can open them from any application, but they’re all just referring to the same file. There’s no disk space cost.

It’ll be much the same in real-world use on your own system, except you can select and create links for multiple files in one operation. And you’ll need to keep in mind that hard links only work with files on the same volume; they can’t span drives.

Using hard links can create complications which you’ll need to keep in mind. If you forget a file is hard linked, for instance, you might open and edit it, thinking there are other copies around. But no, there’s just one, and if you change that, you change them all. (A red overlay is displayed over the icon for a hard linked file to remind you, but this is easy to miss.)

Be careful when deleting, too. In our example, if you deleted Picture.jpg in folder A you might think it’s gone forever. But again, no: the file will stick around until you’ve deleted all the other links.

Individual applications may also cause problems, if they don’t understand hard links. A backup program might decide to back up every hard link as a separate file, perhaps, cutting performance and wasting backup space.

If you’re new to this kind of NTFS trickery it’s probably best to stop here, then, at least until you’ve tested how this works on your own system. And even then, start slowly. Create links for just a few key files before you move on to your 500GB video folder.

But if you mastered this long ago, Link Shell Extension (64-bit) has plenty of other tools to explore. You can use the same copy/ paste approach to create symbolic links, junctions and volume mount points. Cloning copies a folder tree to a destination, but uses hard and symbolic links for all the new files. And there are copying and mirror functions, a backup mode to copy ACLs and encrypted files – even if the current user doesn’t have access to them – and a whole lot more. These can become very complex, and there’s a lot to learn, but the detailed documentation explains all.