[Zubersoft]

I just tried backing up an Android library with a song whose title was "A Hard Day's Night", and had no problems restoring it on Windows 10. Have you used the companion app to check if the missing song files are even in the backup file? I'm guessing they weren't backed up on the Android side. In that case, you could try recreating the backup file and then restoring it on Windows 10 again.

If you export all of the songs to a .msf file, and then import that .msf file on the Windows side, you'll be given an option to update the existing songs. If you do this, it should fix them all.

Mike