Please follow the steps below:
1. An additional driver is required for SJM300/500 to be detected by Windows 10, 8.1, 8, 7, Vista and Windows XP via Thunderbolt.
Please download the driver from: http://www.transcend-info.com/Software/1325/
Install the driver before connecting SJM300/500 to your Windows platform via Thunderbolt.
2. Format SJM portable hard drive to FAT32, NTFS or exFAT in Windows operating system.