Windows sometimes fails to assign drive letters to USB Drive, there is even more problems with network drives in your Computer where drive letter conflict may occur between USB and network drives, though you can assign drive letter for the USB drive from disk management console in Windows, you can automate it with USBDLM aka USB Drive Letter Manager is a freeware Windows service that gives control to you over the drive letter assignment to USB Drives. Since this tool runs as a Windows  service, any logged in user can change drive letters without admin privileges.

USB Drive Letter Manager

USBDLM features

  • Reserves letters for the USB drives , they will  not be used for local drives
  • Shows a balloon tip with assigned drive letters.
  • Remove the drive letters of card reader until the card reader is inserted
  • Checks if drive letter used by network share of current logged in used and assigns next drive letter that is available
  • Assign a drive letter for the specific USB drive by putting an INI file on the drive
  • Assign a letter from a list of new default letters, also dependent on many different criteria as the active user, drive type, connection (USB, FireWire), USB port, volume label, size and others

Whenever an USB drive is plugged in all above functions will be applied immediately.


Download the zip file and extract its contents to a folder. Rename USBDLM _sample file to USBDLM.INI, open it and assign the new default drive letters for USB drives (for e.g. K,L, M) so that these only will be assigned to USB drives whenever they’re connected to your Computer and there will be no drive letter conflicts with network drives in your Computer.

Similarly you can configure drive letters for the Network drives not the local one in the configuration settings file. Once you made the changes, save them and close the file. If you logged in as a administrator run install command to run the service. You can uninstall the service by using uninstall command in USBDLM folder.

USBDLM works on Windows XP/Vista/7.

Download USBDLM