Files aren't backed up

I need help.  New 4T My Cloud and downloaded trial of WD Share. Started a custom backup selecting all of my and other users data folders. WD Share has backed up 49 GB worth of data but 64 GB is not being backed up.  These files show in the right side.When I click on the “view files” link and look at the files and result, I see a combo platter of computer users, files types, and results.  Files range from Outlook pst and ost, to media, images, movies, etc. All other users have been logged off and other apps closed but to no avail. file sizes ae from less than a kB to several GB. Results column include: “file pending backup” and “the process cannot access the file because it is being used.”

This has been going on for a week and the only change in the list is that there are now 315 files that won’t back up instead of the original 309.

Any suggestions?

Thanks.

Have you tried basic troubleshooting steps like restarting the computer, stopping and running the backup or powercycling the drive?