I'm going to write this out step-by-step just to confirm that I understand the process you're taking:
- you rip a CD using whatever software (not relevant)
- you rename the files and move them to a folder where they will presumably stay
- you import the tracks to rekordbox, analyse, adjust beat grid, add hot cues / cues etc., you then lock the file
- you close rekordbox
- at a later time, you re-open rekordbox and the files do not play; they show as missing
Is that correct? Is there anything else missing from the steps above that might be relevant to the situation?
Here are some additional questions for you:
- Are you putting the files on an external hard drive?
- What application are you using to rename / manage your files?
- Are you using iTunes at all?
- What are the filetypes?
- What version of rekordbox are you using?
- Which operating system version?