How to unassign a Drive Letter from a USB Hard Drive

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Recently bought a 2TB WD USB Hard Drive (spinner).  Similar to all my other USB devices when it was plugged into a USB port on my Windows 10 computer, the computer would automatically assign the drive the next available drive letter (eg: L).

Yesterday, while the drive was attached (with the letter L dynamically assigned), I though about “maybe” partitioning the drive into 2 partitions so I went into Disk Management, right clicked on the drive and then clicked on “change drive letter and paths” just to view the options, but then “cancelled” out of everything making no changes.

Apparently that was enough to assign the drive the letter L, as now whenever the drive is attached to the computer it comes up as L.

Anyone know how to un-assign a drive letter to a USB HD and go back to letting the computer assigning a dynamic drive letter once again?

Windows 11 Pro v24H2 and Windows 10 Pro x64 v22H2

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Unplug the USB drive
Open an Admin Command window (Open a Run box (WinKey + R), enter cmd, press the Ctrl + Shift + Enter keys at the same time, and click Yes to the UAC query box that opens.)
At the prompt enter:

net use L: /delete

Reboot
When you connect the USB drive it should assign the next letter.

HTH, Dana:))

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Thanks, but this command appears related more to Network and Shared devices vs USB Hard Drives.  No?

Windows 11 Pro v24H2 and Windows 10 Pro x64 v22H2

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Drive letter assignments are stored in the registry so, if the above doesn’t work, open Regedit and go to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices.

Each “currently assigned” drive letter will appear as separate \DosDevices\{LETTER}: REG_BINARY keys with data that ID’s the specific drive it was assigned to.

Simply delete the one containing the drive letter you want to remove and reboot.

BTW, all the other keys you’ll see at that location are for every storage device your PC has ever recognized as being attached to it; regardless of whether it was assigned a drive letter or not.

This Windows Ten Forums link contains more details on how Windows handles auto-assigned drive letters and how to deal with removing them when you accidentally assign one.

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Thanks for the info.  However other articles that I previously researched say NOT to fiddle within the Registry as some of these settings are linked to other settings within the Registry and things can go bad.

Also some comments as respects this can/may remove the disk letter, but then the system doesn’t auto assign a letter with the result is the drive doesn’t show up in File Explorer?

This is my backup drive and cannot afford to lose access to it.

Thoughts?

Windows 11 Pro v24H2 and Windows 10 Pro x64 v22H2

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Tex,

You can also look into USBDLM (USB Drive Letter Management) a free program that lets you control what drive letters are assigned to USB devices. I use it to insure that when I plug in one of my 6 backup spinners it will always be assigned letter I: and miscellaneous USB devices are assigned x-z. It’s free and very useful

May the Forces of good computing be with you!

RG

PowerShell & VBA Rule!
Computer Specs

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Thanks for the info.  On the surface this program looks rather complex for me to navigate.

Also, I don’t want ensure a drive letter is assigned, I want to remove a static assigned drive letter and go back to the computer dynamically assigning a letter upon device insertion.

Windows 11 Pro v24H2 and Windows 10 Pro x64 v22H2

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Tex265 wrote:

Thanks for the info. However other articles that I previously researched say NOT to fiddle within the Registry as some of these settings are linked to other settings within the Registry and things can go bad. Also some comments as respects this can/may remove the disk letter, but then the system doesn’t auto assign a letter with the result is the drive doesn’t show up in File Explorer?

My system is setup such that Windows “dynamically” assigns drive letter G: to new drives and I’ve used the registry removal trick to remove \DosDevices\G: when it got assigned to a specific device and never experienced any problems with explorer not recognizing the same device and auto-mounting it as letter G: after rebooting.

To trick to avoid problems is, don’t have the drive plugged in when you remove it’s entry in the registry and always cold reboot before reconnecting it (i.e. full power down/restart “without” fast start or hybrid shutdown.)

BTW, there are a lot of other ways to remove a drive letter in Windows 10 and Windows 11 although some of them will remove all assigned drive letters except the ones currently in use when you use them.

I.e. if you’ve assigned a particular drive letter to specific removable drives (in my case B for my Backup disc and R for my Rescue disc), those drives will no longer have those drive letters but will get “dynamically” assigned a drive letter per normal explorer operation!

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Tex265 wrote:

Thanks, but this command appears related more to Network and Shared devices vs USB Hard Drives.  No?

The different drives that a Windows PC sees and accesses if attached internally or externally such as an USB drive is considered a Network by Windows even if it is a Shared device.  When Windows detects a new drive it will select a drive letter and associate that drive letter to the hardware ID of that drive thus remembering that drive when it sees that hardware ID and use that letter.  This information is stored in the Registry.  That command simply deletes those settings from the Registry so the next time you plug it in Windows will not know the hardware ID and thus set it up like a new drive with the next letter to assign.

HTH, Dana:))

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So does this then do the same thing that n0ads is suggesting by going into the Registry vs a Command Line?  Or, are they two different approaches?

Windows 11 Pro v24H2 and Windows 10 Pro x64 v22H2

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Tex265 wrote:

So does this then do the same thing that n0ads is suggesting by going into the Registry vs a Command Line?  Or, are they two different approaches?

They are basically the same…a command to remove that Registry key or directly deleting the key in the Registry using the Registry Editor. I think the command is an easier way to go.

HTH, Dana:))

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Tex265 wrote:

Anyone know how to un-assign a drive letter to a USB HD

I always assign a fix drive letters to my external drives, like : W,X,Y,Z and don’t let Windows assign drive letters (only exception if someone brings a USB flash drive..)

* What’s wrong with L drive ?

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