WD 4TB USB drive continually opens File Explorer

I have just bought a 4TB WD Passport USB drive Ser. No. WXG1EB8CU73H. Using Win 10 on a dell E6540 Latitude.

All seemed to be working OK but the USB drive started opening File Explorer at regular intervals of approx. 30mins.

Auto Play was on to open File Explorer when I connected it to the USB 3 port and a solution was to disable auto play so that when I connect it to the USB 3.0 Port a pop up window appears and asks what I want the drive to do. That worked for a while but now the pop up window continues opening and asking what I want the drive to do despite it being already connected to the USB port. Any ideas how to fix this?