I also have the same problem.
I had recently reformatted my WD drive, installed the latest version of the software and now it’s taken about 4 hours to (Initial) backup less than 1 GB of data with a ton of missed files that it says it can’t find (I checked the path, they are where the software says they are missing from). None of the files are in use, are mostly video files and documents.
It seems like the latest version is knickered up IMO, as I was able to back up some files using the File Backup selection before I installed the software update and it only took a short period of time.
How can I revert to the previous version of the software?