Each day, upon waking my MAC, the contents are not visible.
I cannot eject the HD by dragging it to the trash, or selecting eject in finder. I have to “Force Eject” to unmount it.
After ejecting, I unplug the UBS from my Mac. After reconnecting, all of my data is visible.
After the MAC goes to sleep and is reawakened, the content is again no longer visible and I have to go through this process again.