So what is the big deal about USB drive letter or the letter assigned by windows OS (XP/Visa/2000) when you plug in their USB drive or USB hard drive. I guess it doesn’t matter for most folks until one tries to automate backups.
I never cared about how my windows PC assigned drive letters to my USB flash drives until the day I tried automating backups. On my backup software I had hard coded drive letters – J:\\ for USB flash device and H:\\ for USB external hard drive. I had to follow the sequence such that I would plug in external hard drive first followed by USB flash drive so that windows does its auto letter assignment in the sequence.
It was a real pain that I had to follow the sequence – so I started googling and found this nifty program USBDLM which let me control USB drive letter management.
What is USBDLM?
USBDLM is a Windows service that gives control over Window’s drive letter assignment for USB drives. Furthermore you can define new default letters for USB drives and much more.
Setting USBDLM was real simple. You download the zip file from here, unzip the file, set necessary drive letter management in the configuration file USBDLM.ini and start the executable. You can also have this run at the windows startup, so that the next time you insert a USB based device, the drive letters gets assigned based on configuration file.
Here is my “simple” config file for my U3 device.


Sasi………real good info. Thanks.
Running the executable will not work. It’s a service. Start the _install.cmd to install and start the service. The service start now when Windows starts, no need to add something to the Windows Startup folder.
Uwe Sieber