Yes as it says personal files (pictures, videos, docs and music). Here's an application that does a backup of the OS. As you see they download the software and reboot into the software. Because when windows opens it opens system files and those file can't be backed up while they are open. So you reboot and run the software that loads instead of Windows. Because Windows isn't running you can back up the OS.
I work in the software application field and it's just like you can't back up a database if users are logged in.
YOU NEED ALL FILES CLOSED WHEN DOING A OS BACKUP. Personal files aren't opened when Windows boots.
A backup is backing up of file. Cloning is doing an entire disk. The ONLY way to back up personal files and system files is to launch an app before Windows loads.
https://www.youtube.com/watch?v=P6iWPwG2v34