USB Drive Letter Manager is a free (for personal use) utility that will let you assign permanently a letter to a USB drive. USB Drive Letter Manager does not have a graphical user interface, you can configure it only by editing an .ini file, which is not that difficult though.

Running as service, USB Drive Letter Manager automatically solves conflicts between USB drives and network or subst drives, moreover, it keeps default / permanent letters for USB drives. All functions are applied to USB drives at the moment they are being attached, when the USBDLM service starts up and when a user logs on. USBDLM runs as Windows service.

Features: check if the letter is used by a network share of the currently logged on user and assign to a USB drive the next letter that is really available * reserve letters, so they are not used for local drives * 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;

Assign letters for a specific USB drive by putting an INI file on the drive * remove the drive letters of card readers until a card is inserted * show a balloon tip with the assigned drive letter(s) * define autorun events depending on several criteria, and more.

Here is brief information I hope you find useful, explaining what you should do in order to prevent Windows from changing a letter you don’t want changed.

Install the program by running the install command file in its directory, then create in the directory of the program a USBDLM.ini file by copying one of the already included ini files and renaming it.

Paste inside the USBDLM.ini the following lines:

[DriveLetters10]
DeviceID=Seagate FreeAgent USB Device
Letter=F

[DriveLetters20]
DeviceID=WD 3200AAJ External USB Device
Letter=H

Replace the drive descriptions above with the descriptions of your own drives and the assigned letters F and H with the letters you need to assign. You will find the descriptions of your USB drives (you can use their “friendly name”) by opening the Windows Device Manager (Computer > Properties > Advanced System Settings > Hardware > Device Manager). You can add more drives to the ini file [DriveLetters30], [DriveLetters40], etc.

• Download USB Drive Letter Manager 32bit or 64bit