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Solved: Forcing a certain drive letter on a USB drive

Discussion in 'Windows 7' started by Alex Ethridge, Oct 22, 2013.

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  1. Alex Ethridge

    Alex Ethridge Thread Starter

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    Using Windows 7.

    There are two hard disks of different brands used alternately for off-site backup. Norton Ghost 15 is the backup program that images the drive nightly. The two disks are swapped daily and one is taken off site.

    Problem: As long as the two drives were identical in size and brand, they both assumed the same drive letter and Ghost had no problem. Now that one of the drives have failed and was replaced with one of a different brand, they assume different drive letters and Ghost fails.

    I have tried to understand how USBDLM can force the same drive letter when they are swapped. The way I understand it is there is some kind of INI file placed on the USB drive; but, I just can't understand exactly what goes into that INI file.

    Yes, I have read the USBDLM help file; but, it seems to assume a level of knowledge of the terms it uses that I don't have.

    I would like to use USBDLM; but, I'm not stuck on it if there is a better solution.

    Thanks for reading.
     
  2. TerryNet

    TerryNet Moderator

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    This idea may be just plain dumb, but have you tried using Disk Management to change the drive letter to the one you want? Even if that works the chosen letter may not "stick."
     
  3. Alex Ethridge

    Alex Ethridge Thread Starter

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    It doesn't hold when the drive is changed.
     
  4. throoper

    throoper Trusted Advisor

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    It sounds like the drives now have different DiskID's recorded and Windows won't assign the same drive letter to them.
    That doesn't make a lot of sense, though. When a drive is plugged in it should get the first available drive letter (usually E:\ or F:\). When it's removed, that letter should become available for the next drive.
    Is that not happening?
     
  5. Alex Ethridge

    Alex Ethridge Thread Starter

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    That behavior would make too much sense so I guess that's why Microsoft chose for it to not work that way.

    Seriously, these drives don't work that way and my experience is USB drives in general do not work that way. I do a lot of USB drive swapping so my familiarity with this problem is thorough.
     
  6. DaveA

    DaveA Trusted Advisor Spam Fighter

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    Well on the wife's machine, she had a additional internal hard drive installed. When she fire up the machine with the new drive, she had connected her external drive "E" that she had been using. So the new drive became the "F" drive, and now what ever external USB drive or thumb drive she uses gets the "E" drive letter, as it is the next available drive letter, unless she already has another USB drive connected.

    What drive letter are you trying to use each time?
     
  7. Alex Ethridge

    Alex Ethridge Thread Starter

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    Yes, I understand that. Internally connected drives always get priority and always set drive letters in alphabetical order; but, it does not work that way with USB drives. As long as the two off-site-storage drives were the same brand and model, they assumed the same drive letter when swapped. Now that they are different brands, they take different letters when one is disconnected and the other attached.

    And, yes, we are using the proper disconnect procedure.
     
  8. throoper

    throoper Trusted Advisor

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    My guess would be that somewhere down the line one or both drives were assigned a letter with DM and that's been recorded in the registry matching that drive to that letter.
    On xp you could go into HKLM\System\MountedDevices and delete the data for the drives (DOSDevices and it's matching Volume value) and windows would then treat the drive as a generic volume and assign it the first available letter rather than the fixed letter. I don't know if that will work on Win 7, but I peeked at that key and it looks the same so I would think it will work.

    Another thing you COULD do, since you have USBDLM, is to set a port to use a specific drive letter.
    Any USB device plugged into that port will use the drive letter assigned to that port.
     
  9. Alex Ethridge

    Alex Ethridge Thread Starter

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    That's the kind of stuff I don't understand. I've read the help and am still reading it for the last hour.

    It is simple only for those who understand it.
     
  10. Alex Ethridge

    Alex Ethridge Thread Starter

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    Sorry if I sound agitated; I'm just getting more and more frustrated with the author's help file. The help file is just a little too much over my head.
     
  11. DaveBurnett

    DaveBurnett Account Closed

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  12. throoper

    throoper Trusted Advisor

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    So basically you just need it translated into plain English. :)
    From the beginning to use USBDLM to assign a drive letter to a usb port.

    1: Download the USBDLM.zip.

    2: On Win 7, create a new folder C:\Tools and extract the contents of the zip into the Tools folder. Make the folder permissions so that only admins can make changes if you want the extra UAC security.

    3: Plug a drive into the port you want to use (can be anything, logical drive, flash drive, anything with storage capacity).

    4: Open the C:\Tools\USBDLM folder and run the UsbDriveInfo.exe to find the port number. Select the drive on the left and the data displays on the right. USB Port Name should be the last item (mine is 5-8 for example).
    IMPORTANT!!! Unplug the drive before continuing.

    5: Install the USBDLM service by double clicking the file -install.cmd

    6: Right click in the USBDLM folder and select New>txt document. Name it USBDLM.INI and open it.

    7: In the USBDLM.INI, copy and paste the following code, changing the port number to your port number and assigning the drive letter you want. I've used 5-8 and assigned Z.
    Code:
    [DriveLetters10]
    PortName=5-8
    Letters=Z
    Save the change and you're done. That port should now always assign letter Z (or your choice) to whatever drive is plugged into it.
     
  13. Alex Ethridge

    Alex Ethridge Thread Starter

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    I've been using USBDLM for years but not just like I need to now. That's one of the things that has me stumped. There is no USBDriveInfo in the folder.

    I gotta go out now and I'll look more at this later this evening.

    Thanks.
     
  14. throoper

    throoper Trusted Advisor

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    I wonder if you have a really old version. I downloaded the newest to try it out on Win 7 and I know I had it on my old xp machine.
    It should run if you grab the new zip and just put the USBDriveIfo.exe and the USBDriveInfo.INI in the same folder (doesn't need to be the USBDLM folder). That will get you the port number without having to mess with the current install.
     
  15. Alex Ethridge

    Alex Ethridge Thread Starter

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    Thanks for all the help. I solved the problem.

    I found this web page which explained it clearly enough that, with the help I got here, I finally understood enough to get it done.

    http://www.stepmania.com/wiki/Assigning_drive_letters_to_USB_ports_in_Windows
     
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