The USB drive plugged into Lightning device is in Mac OS X HFS+ partition with journal function enabled. The driver itself contains journal error that has been detected by Lightning device. Lightning server can ignore the warning and mount the partition anyway but may result in potential data lost.
- Fix journal error by connect the USB drive to a Mac computer by plug your USB drive back to Mac computer, go to ‘Applications>Utilities’, start ‘Disk Utility’ and use ‘Verify Disk’ & ‘Repair Disk’ function to fix the journal error.
- Eject properly by using 'Eject' function.
- Please make sure to use 'Eject' function before remove the USB driver from the computer physically.