Cant Access Some Folders on PR2100 - Win 10 Explore resets itself

I have noticed on a number of folders lately that when I try to access through Win 10 Explorer, I can see the folder but cannot access. If I try to select it or access some folders, Win 10 explorer just closes down and there is a refresh/reboot of the desktop screen (computer is NOT rebooting). It seems the explorer reboots/resets itself.

How can I fix?

It seems a system specific issue and can check after updating your Windows Operating System if available or contacting Microsoft Support.
However, you can perform a System Diagnostic Test to get confirm about the health of the My Cloud. You can follow the below link to run Diagnostic Test. Only WD Red drives are recommended to use with My Cloud Home Duo enclosures.