This particular issue has been discussed at length in the past in several prior threads. The solution is to use the My Cloud Dashboard to eject the USB hard drive (and remove it). Then while still within the Dashboard access the Shares page and remove all entries for the USB hard drive share including those with the “_x” numbering. Then reconnect the USB hard drive to the My Cloud and the problem should be fixed.
Just a few past threads discussing this issue:
https://community.wd.com/t/new-release-firmware-release-04-04-02-105-1-27-2016/148441/69
https://community.wd.com/t/mycloud-creating-numerous-aliases-for-same-drive/160161
https://community.wd.com/t/usb-drive-makes-new-name/152675
https://community.wd.com/t/dublicate-shares-after-reboot/153348
