My book 5TB keep disconnecting

I have one My Book 5TB and one My Book 6TB for mac connected to directly to the usb 3.0 port of my Mac Mini. Lately, both external drives disconnect on its own. I can see the files but I can not open them. I have to unplug and plug usb back for it to work (for a while). The My Book 6TB for mac is used for time machine. It will not even finish the back up and got disconnected.


Make sure these drives are plugged in directly into a wall outlet.

Also try using the USB 2.0 port just to verify if they disconnect from that one as well.

I have been using them over a year with no problem, it just happens last month. They are plug into electrical outlet and my Mac Mini only have 4 usb 3.0 port.