Having two computers in our house, I could identify that as a result of this bug, you find yourself in one out of two situations. In both cases you have a way to have your files backed up, although, of course, not as practical. (If you are satisfied with the continuous backup running permanently, you will not be interested by the following).
Situation 1: If you can see a small “clock” icon at the right of the “Set Backup Frequency” button, though the automatic backup no longer works you can still launch it manually. To do so, click the “clock” icon and just press the “launch backup now” in the pop-up window. Naturally, it will take some time to complete, especially on the 1st relaunch.
Note: in situation 1, NEVER click the “Disable backup”, otherwise you will fall in situation 2 with no return.
Situation 2: If no such icon is present, you can still select “Continuous Backup” in the “Set Backup Frequency” window (just forget the error message if any), and then click the “Enable backup” button in the main window. This will start the process, which should work properly.
If you don’t want to have the continuous process permanently running on your computer, you can still suspend it. To do so, click the “Disable backup” button – changing the option to “Scheduled Backup” will have the same effect (as the scheduled backup is no longer working).
The disadvantage of situation 2 is that controlling the completion of the process is uneasy.
For information : after reporting an incident to WD, which initiated a series of many manipulations without success, I was told that the problem was due to a Microsoft module and hence beyond their responsibility. Finally they recommended either to use third party software, or to carry out a complete reinstallation of Windows.