After hard shutdown, Audacity won't start
On Mac, this was really annoying.

Based on this link, do the following:


Go to /Users/Myname/Library/Application Support/audacity (replace Myname with yours of course)
Open file audacity.cfg in text editor
Under section [Directories], find TempDir, which may look like this: /Users/Myname/Library/Application Support/audacity/SessionData
Go to that folder, and delete file audacity-lock-Myname