Map a fake drive letter to a folder with subst.exe

October 8, 2007October 23, 2007 Vide Tips, Windows, Windows 2003

We all know that aberration called “Drives letters” in Windows, a present from the old DOS days. So, maybe you are interested in how to map a fake drive unit (let’s say N:) to an existent folder (for example, C:\Windows).

It’s really easy with substr.exe, all you have to do (once you know this program does exist, naturally) is:
subst N: C:\windows

now if you enter in N: you will see the Windows folder’s contents. This is done on a per-user basis (every user can have its N: pointing to a different directory) and it disappears on the first reboot.
If you want to have it permanent, there is a really nasty and hidden trick, creating a new key in the registry.
You have to go to
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices

and there create a key named with the drive letter you want, colon included (N: in our example) and with this value:
\??\c:\\windows

you can obviously change c: and windows for whatever folder you want, but remember to double the backslash after the unit letter, because it won’t work with a single backslash.
Reboot and enjoy your new N: :)

10 thoughts on “Map a fake drive letter to a folder with subst.exe”

David H says:

October 22, 2007 at 21:04

Thanks for the nice tip!

But I think it should be subst N: C:\windows (In Windows XP at least)

Reply
Vide says:

October 23, 2007 at 10:13

WTF, really I don’t know why I put this “r”… thanks for the correction :)

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João Sena Ribeiro says:

March 28, 2008 at 02:48

You have no idea for how long I was looking for this… Many, many thanks… :)

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Genius says:

July 22, 2008 at 06:39

You need to create a string, not a key, get it right

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Navin says:

September 2, 2008 at 21:49

Works!
Great Trick…

Reply
zepharim says:

June 23, 2009 at 17:03

How would i do this for a network path?
eg:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\DOS Devices
\??\\\MyDFSServ\User

This below works great but i need to do this with the network using the subst not the Net Send as it will create the drive letter but not show the drive letter in my voice editing software. However, the subst method drive letter will show up in my software virtual drive list.
\??\c:\\windows

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- Helder Magalhães says:
  
  August 18, 2009 at 19:03
  
  > How would i do this for a network path?
  
  You’d use something like “net use DRIVE_LETTER: \\SERVER\SHARE” ;-)
  
  Reply
  - zepharim says:
    
    August 26, 2009 at 18:27
    
    Hi Helder,
    
    Thanks for the reply, howvere, i was refering to Not use the Net Use way but with the subst.exe
    
    The reason being is that the Panasonic Voice Editor Software will not recognize the net use created drive letters in its Drive list when browsing – however, it recognizes subst drive letters and includes them in its browser list.
    
    the permenant drive letter mapping via the above article works for local mappings but not network mappings via subst.exe
    
    At this time the only method i could get it to work, was to map the network path via net use and then use the permenant subst drive method to map another drive letter to the new net use created drive letter
    
    My questions was how to eliminate the net use altogether and only use the subst.exe to map 1 drive letter to the network path.
    
    I hope this is understandable lol
    
    Thanks again,
    you Rock!!!
    
    Sincerely,
    Z
zepharim says:

June 23, 2009 at 17:04

PS.
Thanks for the great advice as it is awsome

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MARK says:

February 6, 2010 at 13:32

Thank the GODS!! Well… you!! I have spent hours playing with settings and restores and more… when my drive swapping (and playing) ended up with boot drive as D:\. Couldn’t install programs easily to sort out some temporary stuff… the drive subst worked a charm!!!!

Cheers.

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