No Drive Letter for USB or Firewire Drive
When you connect your USB or IEEE 1394 (Firewire) storage device (hard disk or USB drive) to your computer, Windows will pop up a notification messages that showing USB Mass Storage Device, and then Disk Drive was found. However, you just simply can’t access the drive, and there is no automatic “Autoplay” prompt too, if you enable it.
The USB or Firewire storage drive doesn’t show up (not available and not accessible) in Windows Explorer or My Computer window, although it has been detected, even if the drive has been used properly before in the same computer. In the Device Manager, everything including USB Hub and USB Root Hub, shows working properly. In some cases, it also shows a USB or Firewire storage drive attached and the drive it is working, and the USB or Firewire drive will appear in Disk Management of Computer Management in Microsoft Management Console (MMC) too.
Another symptom to the problem is when you insert the USB or Firewire drive, a “Safely Remove Hardware” icon will appear in Windows notification area (system tray). When you double-click on the icon, the drive appears in the list, but when you display the details of the disk (by double-click on the drive or select the drive then click on Stop), there is no drive letter attached to the drive.
The cause for this problem is that all drive letters are already assigned to other devices or mapped network drives, making no additional drive letters available. Or it may be caused by the drive letter that previously assigned to the drive has been taken up by a mapped network drive or other storage device.
Resolution is to disconnect mapped network drives or other storage devices, freeing up a drive letter or the previously assigned letter to assign to the additional storage device. If you can see the drive in MMC Disk Management, right click on it, and select Change Drive Letter and Paths, then click on Change. Select a drive letter that is unused and click OK. The USB or IEEE 1394 drive can now be accessible.
It’s also possible to change drive letter to a free one via registry.
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Entries (RSS)
May 16th, 2009 07:58
hello. i found that if i change my usb external drive letter, whenever i try to perform a search on it and STOP it before it finishes, explorer.exe freezes and i have to close/lauch it via Task Manager in order to continue working.
this wasn’t like this when the letter was automatically assigned by windows, and reverting it to that letter doesn’t solve this problem.
any suggestions?
March 26th, 2009 23:05
I had a similar problem. The only way I could find was to disable it in decide manager and then enable it. Works fine now.
August 15th, 2008 18:00
Anthony Maw post #31 – thank you, you’ve fixed my problem. Am on Vista and updated to Vista SP1 when a previously recognised external USB drive doesn’t show in Explorer anymore. Followed your instructions re: Show Hidden Devices and it worked! So thanks again.
August 6th, 2008 10:24
Funny thing is that I went into MMC and accessed the drive via right click / explore… never thought to look for a conflicting drive letter. But you were right on the money. Thanks!
July 22nd, 2008 23:22
This was exactly the information I was looking for. I knew what the problem was but I didn’t know where to change it. Thank you.
June 11th, 2008 04:27
the article described my problem to the t but the solution was one i had already attempted and which had failed. after going through disk mgmt and assigning a drive letter i am able to explore it ONLY through disk mgmt, it still will not show up in my comp or explorer. furthermore, when i disconnect my usb drive and reconnect it later i have to follow the same procedures to access it, additionally, the letter i had previously assigned to it is no longer available in the drop down menu of available letters. the device works fine on all other computers and OS’s, i’ve had this problem for almost a year with no solution. and no, i have no other drives interfering, just the c: and a cd drive. any help would be appreciated
May 26th, 2008 08:09
Great article. It is well written, gets straight to the point, and best of all, solved my problem. Thank you.
April 30th, 2008 03:22
No Drive Letter for USB or Firewire Drive article…Thank you. This article really helped. Have a great day!
April 17th, 2008 03:46
The problem has two possibilities: One is that a mapped drive letter supercedes the physical drive letter that Windows wants to assign. The solution is to change the highest mapped drive letter, like E: or F: drive to a letter lower down like G: or H: and then remount the USB drive. This issue is documented on a M$ KB. The other possible cause of the problem is that the volsnap.sys driver does not recognize the external USB device volume and thus does not assign it a drive letter. The solution is to open Device Manager, click View and then Show Hidden Devices. Down the list under Storage Volumes there is an Unknown Device. Right click on it, select Update Driver and let it automatically search. It should reinstall the drive as a Generic Storage device and then correctly assign a drive letter after that.
April 17th, 2008 03:44
The problem has two possible causes and different solutions:
One is that a mapped drive letter supercedes the physical drive letter that Windows wants to assign. The solution is to change the highest mapped drive letter, like E: or F: drive to a letter lower down like G: or H: and then remount the USB drive. This issue is documented on a M$ KB.
The other possible cause of the problem is that the volsnap.sys driver does not recognize the external USB device volume and thus does not assign it a drive letter. The solution is to open Device Manager, click View and then Show Hidden Devices. Down the list under Storage Volumes there is an Unknown Device. Right click on it, select Update Driver and let it automatically search. It should reinstall the drive as a Generic Storage device and then correctly assign a drive letter after that.
Anthony Maw, Vancouver, Canada
mailto:anthony@maw.bc.ca
tel/sms +1 604 318 9994
March 18th, 2008 13:00
This information really helped. My TSonic 610 MP3 player was not getting assigned a drive letter on Windows XP. I followed the instructions and went to Disk Management and assigned a different drive letter to the MP3 player. The problem was that the drive letter was already in use by a mapped network drive. Thanks a lot for sharing this information.
March 15th, 2008 20:01
I had a similar problem and I was able to resolve it. I found that the USB port connecter was not making complete contact with the hard dsik drive. I pressed it a little hard until all the pins were inserted completely. Then I plugged the USB cable to my computer and was able to see it in device manager in “Not initialized” status. To initialise it I had to format the drive and lose all the data in my external hard disk.
If I can remember correctly I noticed this issue after my computer crashed and after restarting my computer, it was running the disk check program which was deleting some indexing or something like it. These files were part of my external hard disk.
December 1st, 2007 12:46
I installed a new 120 gig Seagate hard drive with OEM install CDs from IBM/Lenovo for my Thinkpad. I’ve spent three days trying to solve this problem; I have tried the registry solution presented here, the disk management solution, using Acronis Disk Director Suite, and anything else I could find on the web TO NO AVAIL. I tried to delete the keys and that worked, but once I try to plug in any type of non-hard drive based device Windows XP Pro acts like a blind man with Alzheimers: it thought my USB flash drive was a PCI MODEM!
If I switch back to my trusty Fujitsu (which used the same system restore CDs by the way) everything is detected with no problems. WTF. Seriously Microsoft, go poke your eyes out with a stick. You won’t even stand behind your own product- charging $99.99 – $550 for incident support is worse than highway robbery. It’s like selling cars without a steering whell and charging for brakes. Keep it up and this life-long PC user who has less and less time for foolishness will buy a Mac. That’ll teach you. (yeah, I know it won’t, but it felt good saying it…).
November 29th, 2007 04:24
Ok, here is my usb problem
I have a user that when you insert his USB device it assigns it to a network drive. I go into the computer management and change it to another drive. It see it fine. I then plug in a new usb device and it once again reverts to the network drive. I does not keep the setting for the USB that I had assigned to it. It is on a windows XP environment and the system is locked down so that users cannot access the internet without prior approval. The user has had access with the usb drive in the past and I can change it but only for that USB drive. I have gone into administrative tools, computer management, service applications, services, MSsoftware shadow copy provider, then start-up type: set to “automatic” and the service status I clicked start thinking that this might work. It did not. Anyone with a suggestion as to how to solve this I would greatly appreciate it.