Backup including files not working properly.

Hi Friends,

I have some trouble with a database backup (including the tracks). I recently successfully did a backup. I included all files to have them on one place instead different folders from the last years. I now opened rekordbox to create some new playlists and some files are missing. I can see the waveform, when I click on the waveform to prelisten there is no sound. When I search for missing files Rekordbox tells me, no files are missing. Why the heck it is still a problem to properly backup the library in Version 5.4. Any advice? Thank you...

@rekordbox: You created already 5 versions of Rekordbox and you still have no solution for people who want to reorganise the file library on the hard drive (not the playlists/collection). Relocation or Moving 1000s of tracks is not an option. You really should give your users a way to move the files and relocate them easier. times are changing, so people change ways how to structure files. 
Please help!!!