In your Windows Start menu click on “control panel”. In the top right side of control panel there is a search box. In the search box type system. In the results, the first option should be “edit the system environment variables”. Click on that.
The system properties Window opens. Click on the “environment variables” button at the bottom of that window.
In the lower box for “system variables” click the NEW button. In the Variable name section type
Make sure its all caps and has the underscore. Also be sure that there isn’t any spaces before or after.
In the Variable value section type TRUE, also in all caps, then press OK. Press OK on the environment variables window, and press OK on the system properties Window. Open Pro Tools and the MP3 option should now work.