mp3s (or most other file formats) contain metadata that list the artist, album, year, genre, etc. These are the tags I'm referring to. When you say your files are going into a folder I very much doubt they are actually being moved anywhere, what you mean is they are displaying as "Unknown Folder" rather than grouping with the rest of the album. This should all usually depend on what's in the tags. Check in a tag editor or even, in Windows anyway, just right-click->properties-> details & see they've got the same values as their fellow, correct files. The R3 will group files as per what it sees in those tags. It does occasionally struggle with special characters.