Windows XP mounting USB drive to same letter as previously mapped network drive

All we need is an easy explanation of the problem, so here it is.

Why does Windows always mount a USB drive as the next drive letter after the last physical drive, even when that letter is already taken by a mapped drive, and is there any way to improve this behaviour?

What happens is I tend to use a few different flash drives on my PC, as well as having both a Blackberry and a personal phone that mount as USB drives when I plug them in to charge. Being on a corporate PC I also have a number of mapped network drives (some set by login script, some set as persistent mappings in my profile).

When I first login I’ll have drive letters like this:

C: - Local Drive
D: - DVD Drive
G: - Login script mapped drive
J: - Login script mapped drive

When I plug the Blackberry in it’ll mount two drives (one for onboard storage, one for the SD card) as E: and F:. If I then plug in another USB drive it will mount as G:, even though that’s already taken by a network mapped drive. This leaves me with the following drives:

C: - Local Drive
D: - DVD Drive
E: - USB drive (Blackberry)
F: - USB drive (Blackberry)
G: - Login script mapped drive
[G: - USB drive - mounted but not visible in Explorer or command prompt]
J: - Login script mapped drive

I then have to go into Disk Management, find the new USB drive that’s mounted to G: and re-assign it to another letter eg Z:, once this is done Auto-Play detects it and throws up its normal dialog, and its browseable in Explorer.

While this is OK to do if you only use one or two USB drives and have admin access to your PC with your login account, its a total pain in the proverbial if you regularly use a whole load of different USB devices, and corporate policy means you have one account for your normal login (that only has User access to workstations), but have to use a different account for any privileged action.

I realize that one possible reason for this is the difference between hardware which is mounted and assigned drive letters at the systen level, and mapped drives which are done at the user level. For USB devices that are already plugged in before login, then obviously they’re mounted before Windows knows what network drives may be mapped. However if you plug the USB devices in after you’re fully logged in and have drives mapped then Windows must know which letters are available?

How to solve :

I know you bored from this bug, So we are here to help you! Take a deep breath and look at the explanation of your problem. We have many solutions to this problem, But we recommend you to use the first method because it is tested & true method that will 100% work for you.

Method 1

For this kind of problem, USB Drive Letter Management (USBDLM) makes wonders. You can allocate drive letters to USB drives, make sure it does not interfere with network drives, …

From their Getting Started section:

When a removable drive (USB flash
drive, flash card reader, portable
hard drive) is attached for the first
time, Windows mounts it to the first
available ‘local’ drive letter. If
there is a network share on this
letter, Windows XP will use it anyway
for the new USB drive because since XP
network shares are specific to the
current user and not visible in the
context of the system where the letter
is assigned. The USB drive then
appears to be invisible. This is fixed
by SP3 in most situations. You can
change the letter assignments in the
Windows Disk Management Console with a
lot of mouse clicks but you have to do
it again for every new device. And,
for USB devices that have no serial
number (in violation of the USB
standards) you have to do it too when
you attach it to a different USB port.
USBDLM can for newly attached USB

check if the letter is used by a network share of the currently logged on user and assign the next letter that is really available

Method 2

You can try the mountvol command:

mountvol g: /d

To get the right VolumeName:

mountvol h: \\?\Volume{blablabla}\

Method 3

The Windows-native way to do this may be DISKPART. It works for me.

From the DISKPART> prompt use:

list volume

to identify the USB drive,

select volume {number}

to choose it then

assign letter={letter}

to set its drive letter.

Method 4

It’s a huge pain and I’m not quite sure why Microsoft didn’t right some extra code to use the next available letter.

You might consider pestering your IT department to change the login script to map the network drive in the latter half of the alphabet instead of “G.” Depending on the size of your operation and the extent of use of the network drive, that might be a huge undertaking.

Note: Use and implement method 1 because this method fully tested our system.
Thank you 🙂

All methods was sourced from or, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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