Hello Sir/Madam. Thank you very much for giving us an opportunity to help you. I am Jins here to assist you. Please remember these things when we deal with your issue. It may take more than one step/answer to solve a problem. So If my answers don’t work or if you are not satisfied, please don’t Rate my answer as Bad or Poor Service, but please Reply back to me by clicking the “Continue Conversation” or “Reply” button and I will gladly continue to help. Remember, only Rate answer after you are 100% Satisfied. Please do not rate an answer, if you are not satisfied.
Is this problem happening only with iMovie, most probably your audio settings may have been changed.1. Open Audio MIDI Setup (/Applications/Utilities/), then check the Audio Output setting.2. Change the Audio Output setting to 44100.0 Hz.3. Quit Audio MIDI Setup.Open iMovie. Check and let me know the result.RegardsJins