I have also this kind of problem.
But I have much more files to save, with a lot of large files.
Files are said to “pending”, I wait, and I wait, and I wait … and it doesn’t save anything at all.
The proccess WDBackupEngine.exe seems having strange behaviours. Some times it doesn’t use ressource, some times it uses 50 or 90% of CPU time (and at this moment it doesn’t save anything)