Audacity 2.3.0.0 and Mac OS 10.13.6 - Got a message stating that another copy of Audacity is running, then the window disappears. Do not see it in the list of running jobs. Do not know how to take care of this. I DID restart the Mac but am getting the same response. I cannot run Audacity. I downloaded another copy of Audacity and got 10.2.0. This didn’t work either. Got a different message saying Audacity.app cannot be opened because the identity of the developer cannot be confirmed.
Download attempt version should be 2.1.0.0.
I’ve run into similar issues with other applications. Go to “system preferences” > “security & privacy”, give your password so you can make changes. Sometimes a little popup box will appear and you can click, “open anyway.” If that doesn’t show up, you have to change the setting to “open apps from anywhere”. As soon as you can open the app, go back and change your privacy setting back to where they were. Leaving it to accept apps from anywhere will compromise your computer to attack. But, once an app has been opened and accepted, you should be able to open that app without issues. I hope this helps.
The current version of Audacity is 2.3.1 https://www.audacityteam.org/download/mac/
See here in the manual: https://manual.audacityteam.org/man/faq_installation_and_plug_ins.html#already