Automatically synchronize a folder from your computer with a folder on your USB drive when insert it
However currently, only one-way synchronization is possible with this tool. This means that it just copies the contents of the hard disk folder to the folder on the removable drive, so changes in the folder on the drive will be discarded.
After installation, right-click on the USBsyncer icon from your system tray and choose 'Configure drive'. This will help you to set up your USB stick for synchronization. Then, choose 'Synchronize now' to perform your first synchronization.
You can download USByncer free from here