This is where 1.5.12 shines. It was designed to bridge the gap, offering:
Ensure your music files are not DRM-protected (like old iTunes files). Standard MP3, WAV, and AIFF files work best. Serato Dj Lite 1.5.12 Mac
Ensure you have enough free disk space (at least 500 MB). Also, check that your output routing is set to Internal Mixing (not External). This is where 1