1. Please check if the JetDrive Lite has become read only or write protected.
2. Go to Disk Utility and choose Info to confirm the file format of your JetDrive Lite.
ExFAT : Supported by both Mac OS X and Windows OS
HFS+ : Support by Mac OS X only
NTFS : Supported by Windows OS only
3. Erase the JetDrive Lite to the file format as per your preference.
Note: Please back up your data stored on the JetDrive Lite before the erase.
If the problem still exists, please contact Transcend Technical Support for more help.