LG 60PH660V User Manual page 200

✎ You can use a Hard Disk Drive (HDD) or Solid State Drive (SSD) as a USB
device for Time Machine Ⅱ only.
✎ It is recommended that you use a USB device with a capacity between
40 GB and 2 TB.
✎ For an SSD, there is a limit to the amount of reading/writing that can be done.
Therefore, it is recommended that you use a HDD.
✎ To remove a USB device, select Quick Menu ➙ USB Device. Make sure you
receive the confirmation message that the USB device has been removed.
✎ If a USB device is faulty, the Time Machine Ⅱ function may not operate
normally.
✎ If you use a USB extension cable, the USB device may not be recognized or
may not work properly.