[maestralien]

Yes, the backup file absolutely should have all of the settings and files. You can check to see if the backup file actually contains this file by using the companion application to view/extract the backup and see if you can extract the file for this particular song. If you want me to take a look at this problem in more detail, I may need to get my hands on the backup file so I can get more information. It's possibly the tablet isn't successfully packaging all of the files in the backup file or that something is going wrong during the restore process on your Windows 10 device.  Is the tablet an Android device?

Thanks,
Mike

Thanks Mike! Yes my tablet is Android (Samsung Galaxy Note Pro 12.2).
However, I tested the backup file through Companion application and that file (pdf) is there, it's been successfully extracted. So the problem should be when restoring the backup in Windows 10 app?
I tried to import the same backup in another computer and same error, same file missing. Please see attached screenshot.
Thank you!