Audio files not being saved as a part of the song project

Hi everyone,

I just wondered if anyone else had a problem with their audio files not being saved as a part of their song projects when they save a file either as a "Project" or a "Folder" in Logic Pro X? For about a year Logic Pro X was working fine and when I saved a project all the associated files including the Audio Files and the MIDI files were being saved as a part of the song but just recently when I have saved some of the songs when I have re-opened the song file the Audio files were missing. And when I say the Audio files I specifically referring to the Vocals recorded through a condenser microphone and the Apple Audio Loops (the blue ones) imported from the Loops Browser in Logic Pro X.

Has anyone else had this problem? And have you found a solution to it? Because I am completely bemused by what could be causing this issue all of a sudden.

So any help will be gratefully received.

Many thanks.