It doesn't seem to be possible to drag an audio clip directly onto the timeline any more without first importing it into the project.
In CS6, I could drag an audio file like a .wav, mp3 or similar directly on to the timeline. CS6 would automatically add it to the project, it would be conformed, and its waveform would appear in the timeline.
In CC, it doesn't add it to the project, and instead it creates what appears to be just an empty placeholder in the timeline. There's no waveform, and no audio is heard when the sequence is played.
With CC, it seems you have to import it into the project first, then drag it onto the timeline, creating an unncessary extra step.
Also, if after importing that audio file into the project you then delete it, it doesn't get removed from the timeline, it just stays there.
Feature is still there, has not changed.
Try clearing your media cashe
Worked for me, too. Tried MP3, AAC and WAV.