The situation is that when playing back a track unless the Software Playthrough(SP) is checked there is no audio. There would be sound coming through the headphones just fine prior to upgrading to 2.1.2. All other players work just fine. Is this a bug? Is there a fix?
You must be leaving something out. Are you overdubbing? What’s the job?
Software Playthrough plays sound that is coming through the selected recording device. Nothing else.
You’ll have to tell us what you are trying to do.