“Audacity is already running” Error on Mac

Audacity 2.1.2, macOS Sierra 10.12.1

After I upgraded my SSD for MAC, Audacity failed to open. The following error message appeared each time I tried to run Audacity:

“Audacity is already running. The system has detected that another copy of Audacity is running. Running two copies of Audacity simultaneously may lead to data loss or cause your system to crash, so is not allowed. Use the New or Open commands in the currently running Audacity process to open multiple projects simultaneously.”

I assumed that it could be a migration issue. I had set the temporary folder for Audacity in the SD card which was not formatted as journaled.

After a Google search and reading several recommended solutions, I tried few of those:

Delete lock file and temporary folder — Failed

1. Delete the lock file in the Audacity temporary folder.
2. Delete the temporary folder itself.

Each time I opened the Audacity after these tasks, temporary folders were created again, and a lock folder was also created in the temporary folder. Audacity failed to open.

Modify the temporary folder details in the Audacity Configuration File — Failed

1. In Finder, Go > Go to Folder. 
2. Type or paste: ~/Library/Application Support/audacity/
3. Click Go
4. Open the audacity.cfg file in a text editor.
5. Modify the TempDir= line to point to a new temporary folder.

Kill the Audacity processes using Terminal — Failed

The process numbers kept on changing and even kill command did not work as expected.

Uninstall and Reinstall Audacity — Failed

Uninstalled Audacity and reinstalled the application. But, got the error again.

Uninstall Audacity > Remove Configuration File > Reinstall—Resolved

1. Uninstall Audacity.
2. Delete Audacity lock file in the temporary folder.
3. Delete the Audacity temporary folder.
4. Delete the Audacity configuration file:
   1. In Finder, Go > Go to Folder. 
   2. Type or paste: ~/Library/Application Support/audacity/
   3. Click Go
   4. Delete file audacity.cfg
5. Install Audacity.

Audacity is working fine now.

For details on Audacity Preferences: http://manual.audacityteam.org/man/preferences.html#stored