I have had my Mixtrack for a few weeks. I was running Serato DJ Intro on a MacBook Pro running Sierra, external HD for audio files. The controller was running fine until today. The left cogwheel platter had major latency, sometimes was unresponsive. Also, I couldn't get the play button to work consistently. The issue moved to both sides. I thought it could be a cable issue but I tried multiple cables, 2 different MACBOOK PRO's and a window 10 laptop.
I am using a external that has older Serato files, crates and iTunes playlists. Could this be the issue? I at a loss and really want this set up to function correctly. Thanks for you help.
What are the specs of the Mac? Try putting music files on the computer itself and not the external. Don't use the external at all but make a folder of files on your desktop and create a crate and test those files in Serato. If playback is fine it's likely the external.