Just what are Windows 7's 'Libraries' and how do they work?

What Libraries are

A Library – say the "Music" Library that shows up in default installations – is nothing more than a collected view of one or more folders.

It's actually a very simple concept, but even that description sounds confusing.

Right-click the Music Library and click Properties. You'll get a dialog much like this:

Note that it lists two folders as "Library locations."

• My Music (C:\Users\LeoN)

• Public Music (C:\Users\Public)

Where "LeoN" would be replaced by your login name on your machine.

Using Music as the example, here's the magic behind Libraries:

The Music Library is simply showing you the contents of the folders "C:\Users\LeoN\My Music" and "C:\Users\Public\Public Music", combined.

Read that again, because it's important. It's very simple, but completely not obvious.

A Library is not a folder. A Library is simply another way of looking at the contents of multiple folders in a single place.

That's all.

Confusion #1: Multiple copies of files

Continuing with example of the Music Library, let's create a couple of files:

• C:\Users\LeoN\My Music\PrivateAudio.mp3

• C:\Users\Public\Public Music\PublicAudio.mp3

That's one music file in my private folder and another in the public folder. It's important to note that these two files are in two different folders.

When we look in the Music Library, we see both files:

So far, so good. The Library's showing us the combined contents of the two folders in a single place.

Now, it gets confusing.

Let's create two different files in those two different locations that happen to have the exact same name:

• C:\Users\LeoN\My Music\Hit_Music.mp3

• C:\Users\Public\Public Music\Hit_Music.mp3

Those are two different files, in two different folders that simply happen to have the same name.

Here's what we see in the Music Library:

It looks like we have two files of the same name in the same place. We don't. We have two files with the same name in two different folders. The Library view simply hides that little fact.

My guess is that over half of the confusion and problems I see related to Libraries are a result of that.

Confusion #2: Where do files go?

So we've established that a Library is not a folder, but rather a view or a way of looking at the contents of multiple folders.

But you can kind of/sort of treat a Library like a folder. For example, you can copy files into the Library.

But if a Library is not a folder, where do the files get placed?

Let's look at the properties of the Music Library again:

I've highlighted the checkmark next to the first folder location. The checkmark indicates which of the actual folders is consider the "default" folder. That's the folder into which files will be placed when they are copied into the Library.

The result is that if I copy a new file into my Music Library, it will actually be placed into the "C:\Users\LeoN\My Music" folder.

Libraries aren't really new

The technology behind Libraries isn't really all that new. In fact, you've been using it since the days of at least Windows XP and probably several versions prior.

It's basically the same thing as what's been happening to your Start menu and Desktop all along.

The Start menu is really a view on two different folders. The specific folders may have changed over time, but on my Windows 7 desktop, my Start menu is actually built from the combined contents of two folders:

• C:\ProgramData\Microsoft\Windows\Start Menu

• C:\Users\LeoN\AppData\Roaming\Microsoft\Windows\Start Menu

Very much like Libraries, the Start Menu is nothing more than a view of the combined contents of two folders.

The same is true for the items on your Desktop as well.

Libraries can be useful

I don't want to completely bad-mouth Libraries, as they can be useful.

For example, if I have multiple Music folders all over my machine – perhaps an iTunes collection, a folder with all my Amazon purchased MP3s, another folder or two or three with my previously collected music – it might be convenient to create a Library or update the existing Music Library to reference all those locations. That way, the Library becomes a one-stop location for accessing all of my music, wherever it might be.

Libraries: My suggestion

Some might label me a luddite for suggesting this, but unless you really understand exactly what Libraries are and are not, I suggest you ignore them completely.

I'd even go so far as to uncheck the "Show in navigation pane" option that you see in the Properties dialogs before. That won't make any files disappear, it'll simply remove the Library view on the folders that contain your files.

Instead, I'd focus on using the actual folders you care about directly.

My guess is you don't care about "C:\Users\Public\Public Music", so all you really need is your own music folder – "C:\Users\LeoN\My Music" in my case.

Reference those actual folders directly rather than trying to use Libraries.

It'll be a lot less confusing and you'll know exactly where your files are.

If Libraries sound interesting to you, and you now understand what they are and are not, then use them as you see fit, of course.

But if you're just not quite sure, they're completely safe to ignore and probably less confusing to do so. Just use the regular folders that you're already familiar with instead.

That's exactly what I do.