I can not playback files that have an .aif or wave extension. In Cubase 6 it was working fine, what has changed since then?
What exactly do you mean “I can not playback”? Do you want to pre-listen it in the Media Bay, before you add them into the project?
If yes, open VST Connections, and find Studio tab. Activate Control Room. This will create Monitor 1 bus. Set your main physical output here, as you Monitor 1. In the Output tab, deactivate your Stereo Out bus – set Not Connected here.
Output of all these windows (like MediaBay, Loop Browser, Import Audio, etc.) are routed throught the Monitor 1 output.