That is a well known and discussed problem with the later firmware. The solution (as discussed in numerous prior threads) is to access the My Cloud Dashboard and eject the USB hard drive. Then while still within the Dashboard access the Shares page and remove all instances of the USB hard drive still listed. Then reinsert the USB hard drive in the My Cloud USB port, access the Shares page again and rename the USB share name back to the default name.
Just a few past threads on this issue that can be found via the forum search (magnifying glass icon upper right):
https://community.wd.com/t/my-safepoints-disappear/160698
https://community.wd.com/t/new-release-firmware-release-04-04-02-105-1-27-2016/148441/68
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
