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USB Key default drive mapping

USB Key default drive mapping

USB Key default drive mapping

We have a problem on my network, we are running W2K desktops throghout the school, we limit access to certain drives and my computer.
When a user logs on and inserts a USB key sometimes it doesn't map to E: (Which is always the next available letter) it instead maps to F: or G:, I can't find any reason for this and when I log on as administrator I can change the mapping to E: without any problem.
We are running a program called "Deep Freeze" which keeps the computer locked down and resets the computers settings upon reeboot so it is not plausable to go round 450+ workstations with a USB key and change the mapping.

Any ideas?
Many thanks,

RE: USB Key default drive mapping

Karl, you're not the only one with this problem.  It's been my experience that every single time, without exception, a USB key takes the drive letter of the first mapped network drive.  I've had to change it manually for a number of users on my network.  I have yet to see a solution to this problem.

Also, if I use, for example, my USB key and remap it to say drive X:, if someone else comes along with a different size/brand USB key it again maps to the first mapped network drive, not X:.  Seems that Windows can differentiate between USB keys, preventing an across-the-board remapping unless everyone has the same key.

I'm wondering if there might be a registry hack that would force the mapping for a new device to a particular drive, for example X:.  It that can be done, all USB keys would be assigned X:.  (I'm assuming that your users would have no reason to map anything else.)

Good luck.  I'll follow this thread since I, too, am curious to know if anyone has found a workaround.


RE: USB Key default drive mapping

I'm not sure if this is directly related to the problem, but we have experienced problems where removeable drive and mapped networked drive assignments can confuse the hell out of windows.

We now avoid this by making sure that we have no network drives mapped until drive H. That leaves windows sufficient drive letters for Pen Keys, Cameras and as many USB drives types that anyone wants to plug in.

It seems that if you map a network drive - say as F - and the computer has a CD-ROM (D) and a DVD-ROM (E), if you plug in a pen key, windows assigns it F, even though F is already a mapped network drive. Explorer then only displays the network drive and the Key cannot be seen until you open Drive Manager.

Regards: tf1

RE: USB Key default drive mapping

The bcastner trick:

Use Disk Manager to re-assign your fixed removable drives.  For example, move your CD Rom/ DVD / IOMEGA devices to high drive letters that are unused.

This creates drive letter "space" below letter F or H or whatever is in conflict.

Your pen drive then will install in the drive letter space formally occupied by your fixed removable device.

RE: USB Key default drive mapping

That would work for a single workstation, but what about hundreds of workstations with different configurations?  Some have CD, some have both CD and DVD, etc.

Do you know if there is a way to force XP to assign drive letters?  If that could be done, then the USB pen drive (or anything else, for that matter) could always be forced to, let's say, X:.  That would work for me since my users are extremely restricted and are not permitted to plug devices into their workstations without permission, so there would not be a need for more than one assignable drive letter.


RE: USB Key default drive mapping

I have to agree with Kevin, we have over 450 workstations and to change the mappings on all of these would be extremely time consuming!
At the moment all our mapped drives are from M: onwards so that should not be an issue. But when USB keys are inserted Windows is skipping drive E: sometimes but not at others. I can't understand why it is incosistent like this. As administrator I can change it back to E: so E: is available but then next time they insert the same key it sometimes comes back as F: or G:!!!

I'm lost for ideas...
Forcing it to go to E: would be an ideal solution...

RE: USB Key default drive mapping

It is just not possible at the moment through group policy or a registry hack.  The disk mount manager will always grab the first available drive letter after enumerating all "DOS" level devices.  This is true for Win9x through Windows 2003.

The disk mount manager is not aware and is completely dumb about the fact that there is a logical drive mapping in place, or planned.

Now this is decidedly non-trivial, but you can under Win2k and XP use devcon.exe to do the removal and opening of drive letter assignments sort of as I suggested above.  You would place devcon.exe in an accesible through the PATH at logon directory such as \WINNT\System32 or \WINDOWS\system32:  http://support.microsoft.com/default.aspx?scid=kb;...

This disables the native hard devices to open room.

In the alternative to disabling or removing devices with devcon, you can use Dispart with scripts.  This is even more decidedly non-trivial, but would allow you do script the move of drive letters to the upper alphabet as I described originally:  http://support.microsoft.com/?id=300415

RE: USB Key default drive mapping

Ok not really related to, but hoping for help. Bought wife new comp 4 X-mas. installed all programs but card reader.Digital camera & jumpdrive worked as removable drives until i installed Card Reader. tried to uninstall software of card reader through C P Add/Remove, but will not initialize. Tried reinstalling software,but says to uninstall previous version of driver. tried to install directly from cd no luck. Has to be a h_key regisrty problem...yes, no? Possibly wrote XP files when 98 was supposed to be the correct driver. Installed from windows 98 folder from matsonic MB driver CD. Bad card reader software? It's an Access 4-in-1 card reader, but googling gives a defunt website link that i assumed was the closest match.Probably went bankrupt trying to provide customer noservice with this problem. tearing my hair out w/ a
%^$$ed off wife.

RE: USB Key default drive mapping


We have the same problem.  We have an application that uses the F drive and to change it would be a huge task.

Several users have usb drives and they are always using the F drive not regonizing the fact that the drive letter is mapped.  I always have to go change it for them or show them how.  This is very anoying.

Also windows will not boot if they leave the usb drive in there computer.


It's only easy if you know how.

RE: USB Key default drive mapping


Move an optical drive to a high drive letter creating room for the USB drive to fill in below drive letter F.

For the boot issue, check the BIOS boot order and disable or place last the use of USB devices to boot.

RE: USB Key default drive mapping

A partial solution is to power up the PC with the key drive NOT installed, then after you insert it, it used an available drive letter.

Something I discovered after installing one of those 8-in-one memory card readers (normally uses 4 drive letters) and having the same problem, is that they don't HAVE to use a drive letter at all. You can make them appear as though they are a subdirectory of an NTFS drive via disk manager in administrative tools.

RE: USB Key default drive mapping

I still have no solution to this problem.  We can not change the mapped drive letter from F to a lower letter.  An application is dependent apon the F drive.

When will MS fix this problem?


It's only easy when you know how.

RE: USB Key default drive mapping

I don't think ms will ever fix this problem, you need to change you application to look to another drive, not an easy solution but the only solution.

RE: USB Key default drive mapping

I think they will fix it.  Maybe in the next version of windows.  The disk mount manager only looks at dos level drives before assining a letter to the USB disk.  Seems like something they will fix.


It's only easy when you know how.

RE: USB Key default drive mapping



We ran into this problem here at work (admittedly with XP, not 2K).

First and foremost... make sure nothing like Daemon Tools is up and running.  If it is, get it out of there.  If it isn't, don't ever install it.  It is a primary cause for headaches of this nature, as it needlessly will swipe one or tww drive letters.  It's been the number one culprit here...

MS recommends when you map drives that you use the *highest* available drive letters (not the lowest), and reserve the lowest letters for external devices and such (like a USB key).

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