26 Drives? Is there a way around the 26 drive limit in Windows?

Home » Windows

Summary: 26 drives appears to be the limit within Windows, with drive letters assigned A: to Z:. There are alternatives to 26 drives that are, effectively, limitless.

This is one of those situation's I've been meaning to get around to for quite a while myself. I have one machine on which I have several physical drives installed, and a USB 8-in-one flash reader that adds 4 more drives, and two CD-ROM drives. On top of that I, too, want to connect to several other machines on my network. I wasn't running out of room, but things were getting tight.

Note how I said "were". There are a couple of good solutions.

•

Hard Disks

We'll start with the physical drives attached to your system.

As we saw in a previous article Can I reassign my drive letters? you can, using the system drive management tool, assign the letters of your choice to your drives, rather than accepting the Windows default. While I don't recommend renaming "C:", the default Windows install drive, pretty much any other drive can be assigned any letter that isn't already in use.

Or none at all.

But at least one of your drives, probably your C:, or Windows installation drive, needs to be NTFS format.

Following the instructions in that article:

• Right click on My Computer and click on Manage to bring up the Computer Management Dialog

• click on Disk Management, to open up the Disk Management Dialog

• Right click on one of the drives that is not your Windows install drive, and then click on Change Drive Letter and Paths...

Doing that on my machine for my external backup drive (E:), I get this:

Now, this time instead of pressing Change... to change a drive letter, we're going to press Add.... This dialog results:

What we haven't talked about is that "or Path" part these dialogs keep talking about. In Windows Explorer, create this folder on your NTFS formatted C: drive:

c:\backupdrive

The name is totally up to you - the only requirement is that the drive be NTFS formatted, and that this folder you just created be empty.

Now enter that folder name in the Add Drive Letter or Path... dialog we have open:

Press OK.

Now you should see the contents of the E: drive.:

Appear within the folder C:\backupdrive:

Recalling that the problem was that too many drive letters were in use, there's one last step.

Back in disk manager, right click on the drive we've been playing with (E: in my case) and once again click on Change Drive Letter and Paths... - it should look similar to this:

Make sure that the drive letter is selected, and click Remove. You'll get a warning, which I'll discuss in a moment. Press OK on that warning, and the drive letter is no longer associated with that hard disk. It's been freed up for use elsewhere. The contents of that hard disk are still available at c:\backupdrive.

The directory "c:\backupdrive" is called a "mount point" or junction. It's the point at which the contents of another drive are mounted. Physically all the contents below that mount point are on that other hard drive, but logically all files are referenced via paths beginning with c:\backupdrive.

The warning you got above is simply telling you that programs which might have expected files on (in my case) "E:" are now going to fail - they'll have to be instructed to look at "c:\backupdrive" instead.

One other thing to note; mount points are treated just like any other directory for file sharing purposes. So if, for example, my "C:" drive was shared out, then by mounting the E: drive in a mount point on C:, it also became available for file sharing.

This is actually quite handy - for example if you have several drives, as I do, you might create a subdirectory full of mount points:

c:\dev\harddisk2
c:\dev\backupdisk
c:\dev\harddisk3

Now, simply by sharing c:\dev, all the hard disks mounted underneath are automatically shared.

Using mount points you can add a virtually unlimited number of drives or partitions to your system without using up any of the precious 26 drive letters.

Networking

(I'm going to assume that you have file sharing already working between the machines you care about. Network setup and file sharing is beyond the scope of this article.)

Network connections can eat up drive letters as well, if you use Map Network Drive:

Or if you make the connection in the command prompt:

NET USE Y: \\leo\mail

In many cases there's simply no need to do this.

In Windows Explorer, in the address bar, simply type \\server\share as the "folder" you want to browse:

In many cases (though admittedly not all) you can simply use \\server\sharename instead of a drive letter to access a remote resource. This means you don't have to eat up a drive letter by mapping a network drive unless you find you really need to.

Putting it all Together

Finally, let's combine all this together.

Machine B has 6 hard disk drives; "C:" plus 5 others. We'll set up mount points on that machine:

c:\dev\harddisk2
c:\dev\harddisk3
c:\dev\harddisk4
c:\dev\harddisk5
c:\dev\harddisk6

Then, still on machine B, we share the directory "C:\dev" to the local area network.

Now, over on machine A, we have a choice. We can map a drive:

NET USE Q: \\MACHINE-B\dev

and we can access all of machine B's hard drives as "Q:\harddisk2", "Q:\harddisk3" and so on.

OR we can skip the mapping entirely, and simply reference those drives as "\\MACHINE-B\dev\harddisk2", "\\MACHINE-B\dev\harddisk3" and so on.

In this extreme case, you can access all the hard disks on both your local and the remote machine without using any drive letters on either.

I'll confess that I do still use drive letters, but mostly as a shorthand. "Q:" is much shorter to type that "\\server\\share". But in most cases, that's the only reason.

Article C2749 - August 8, 2006