I regularly move my mp3 files from my source which is my external which is what i use with serato, but i need to know if there is a way that i can do a scan to update the missing files (the ones with a question mark next to them) and to generally clean up my boxes (i have many duplicates now).

Thanks

wherever you moved them too, re-import that folder, and then re-scan id3-tags.

and you'll have to delete the files that are red, and have the ? mark next to them.