Delete the application Audacity, and the folder
~/Library/Application Support/audacity
(this is where all settings etc. are stored) and re-install it again - preferrably from a fresh download.
If this does not help, your OS may be damaged, your SSD may be full, or any other reason.
Open the audacity.cfg file in TextEdit.
Scroll all the way to the end of the file.
If there are any projects listed under the heading ActiveProjects, delete those lines.
Save the file.
Also inside the audacity folder is a SessionData folder. Delete anything in that folder. If you are not comfortable deleting those files (they are the files used for crash recovery), move them somewhere else (like the desktop) for the time being.