What Share or folder is the Smartware program using on the My Cloud as it’s destination for backups? That error message seems to indicate Smartware is trying to back up to the WDSync Share on the My Cloud. If so perhaps use a different Share, like the default Smartware Share on the My Cloud if not using it already.
Or if backing up to the WDSync Share see if it is set to Private in the My Cloud Dashboard, if so set it to Public and see if the issue continues. In any event if one is using WD Sync and one is trying to use a WD Sync monitored Share on the My Cloud as a backup target/location for Smartware, one may have problems or a conflict between WD Sync and the WD Smartware program.
Edit to add: There is also a much older post of a similar error message (although not the WDSync share/folder name) using Smatware. In that case the suggestion by by another user was to uninstall Smartware, then reinstall it and see if the error message goes away.
