FreeFileSync 一款开源的文件同步软件

FreeFileSync 用户手册:

Variable Drive Letters

USB memory sticks or external hard disks often get different drive letters assigned than the last time when they were plugged into the computer. FreeFileSync offers the following solutions:

Option 1: Specify a path by using a unique volume name instead of a drive letter:
E.g. [Backup-Disk]\folder
replaces E:\folder when the name of the USB stick in drive E:\ is "Backup-Disk".
You can change a volume name by right-clicking on the drive letter in Windows Explorer and selecting Rename.

Option 2: Refer to a disk volume by its unique GUID:
E.g. \\?\Volume{01234567-89ab-cdef-0123-456789abcdef}\folder
A volume GUID uniquely identifies a particular drive partition and will not change over time. To get an overview of all volume GUIDs for mounted drives on the system you can run the mountvol 命令行使用 tool.
 

Note
It is not required to look up and enter a volume name, volume guid or macro manually. Simply select an alternative path from the drop down menu:
Drive letter by volume name