I am making tutorial for students. I am using PPT slides and capturing screen and audio with Camtasia 3.1.5. There is one slide that I would like to do over. Can I re-record a new short video and replace the old section with the newly recorded section? I am using a MAC.
Absolutely. Record as many pieces as you want. You can chop up and trim out parts you don't want and put in new parts. Also, in the editor, you can record audio over the original clip if you just didn't like your original audio, and then mute your original audio so all you hear is your new audio. So whichever method works best for you personally is the one to use.