Preview Speed - Beginners Question

Hello,

when I add  Video or Musik into my Project and then press the preview button the preview Speed is to fast. I Looks like the preview has a double Speed.

When I Export the Project the Speed is correct.

Is there any Option to Change the preview Speed? I rendered the Project - not Change. There is no Change in the Project to run Clips faster or slower.

This is related to my Installation of PRE15 - I do not have the same effect in PRE14.

Thanks for your Reply.

Guenter