When I download an .m4a file from a google site on my MBP (OS 10.8.2), it appears in the downloads folder as an .m4a.mp3 filetype. Obviously, the computer is reading the .m4a as part of the filename, and downloading it as an .mp3. To get it to play, I have to strip off the new tag, but is there a way to get it to just download the file and not mis-recognize the filetype?