Drive Letters by Volume Serial Number
The Volume Serial Number a 32 bit random value, created when a drive is formatted.
Since it cannot be changed by the user offhand it might be a better choice as criteria than the Volume Label.
Furthermore determining it does not cause delays because USBDLM reads it directly from the Disk device instead from the volume's file system.
Determine the serial:
Start -> Run
CMD
C:\>dir u:\*.x
Volume in drive U is TEST
Volume Serial Number is B92B-8000
'*.x' is just a file name pattern which usually results in zero hits.
The UsbDriveInfo tool shows the serial too:
========== Storage Volume on Disk 1 in Partition 1 ===========
MountPoint = U:\
Volume Label = TEST
Volume Size = 15.6 GB / 14.5 GiB / 15.619.129.344 Bytes
File System = NTFS 3.1, 4 KB clusters, 145 MB free
Volume Serial = B92B-8000
FileSystem BS = NTFS
Sample:
[DriveLetters]
VolumeSerial=B92B-8000
Letter=U
[DriveLetters]
VolumeSerial=C8D3-F123
Letter=V
Or several volumes with different serials on one letter (one after the other):
[DriveLetters]
VolumeSerial=B92B-8000
VolumeSerial=34AB-E831
VolumeSerial=A34C-3080
Letter=U
The volume serial can be changed by means of the command-line tool VolumeID from SysInternals.
This way you can create drives with consecutive serials and then use wildcards:
[DriveLetters]
VolumeSerial=BABA-00??
Letter=B