Can't play or record files on my Mac

[TheDoc]

I tried to follow to the letter all instructions to download and install Audacity on my Mac Catalina Version 10.15.6. Audacity 2.4.2 downloads fine and seems to install fine. I can upload an audio file without problems. But as soon as I try to play the audio clip I get the following error message: Error opening sound device. Try changing the audio host, playback device, and the project sample rate. When I try to record a clip I get the following error message: Error opening sound device. Try changing the audio host, playback device, and the project sample rate. What am I doing wrong?

[kozikowski]

I'm betting you're not playing to your built-in speakers or recording from the built-in microphone. What are your devices?

Are you trying to record from the internet, Skype, Chat, or Zoom?

Koz

[TheDoc]

You are correct that my main device for recording and microphone is a Scarlett device which I use successfully with all other Mac DAW's. However I tried changing to the built in speakers and built in mic and got no change whatsoever. The audacity app will load any file be it mp3, wav etc. It just won't play or record and gives me an error no matter which device, or sample rate I use. I tried all of them.

[steve]

If you reboot your computer, then open Audacity (and no other apps), and then import an audio file into Audacity, does it play?