What does the Share name of the connected USB drive indicate? Is there an underscore and a number appended to the name of the USB Share?
IF so this is a well known problem with the recent firmware on the single bay My Clouds where the firmware is changing the name of the USB Share and causes the Safepoint to disappear (its typically still there) because the Safepoint is tied to the Share name of the USB drive when it was created. Once that Share name chances the Safepoint is no longer seen.
The solution is to eject the USB drive through the Dashboard USB icon. Then remove all other USB Share entries listed on the Dashboard > Shares page. Then reconnect the USB drive, and rename the USB Share back to its correct or initial name on the Dashboard > Shares page.
See the following threads where this issue is discussed in more detail:
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
