I was getting an error when launching Audacity.

The error was:

“The system has detected that another copy of Audacity is running.”

However, Audacity wasn’t running at all. Not one process. It turned out to be just a locked file located in /var/tmp/audacity-[your-username].

All you have to do is delete the entire directory and rerun Audacity.

rm -rf /var/tmp/audacity=[your-username]/

Once deleted, Audacity starts right up with no issues.