Originally Posted by Natali

Yes, our program supports iTunes music.
iTunes files have to play in QuickTime Player, so first of all please check
the problem files in QTP.

Have you installed the latest Soundtaxi version (2.7.2)?
If not, please download it from our official site by clicking on "Download
free trial" and install. Use your old license code for activation.

This version has new 'troubleshoot' slider in settings dialog. In case if your problem persists, please try to move that slider step-by-step and find a mode which gives reliable conversion results on your PC.

Let me know if the issue is solved now.