What happened was I downloaded an mp3 file from YouTube's free music resource. I am on an iMac. When I checked the audio in Apple Music and Quicktime, it played back fine in both programs. When I imported it into Rush (1.5.12), it played back as a small snippet of audio from another clip over and over for the full duration of the audio clip. I even tried to run it through media encoder and had no luck. This has happened more than once. I was able to resolve the problem by downloading a different file. Before I sent this response, I relaunched Rush and the original corrupt mp3 file plays back fine now. It seems this is an intermittent problem so if it happens again, I will try to attach my files to this query.