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

Open The Terminal 

Type the command below

killall audacity

Then

Go to the path

the path / var / tmp / audacity- < username / > where < username / > is the username of Linux
 

Open up the folder and look for 

audacity.cfg

 how to find files audacity.cfg that is in ~ / .audacity - data / 

Or open audacity.cfg 

and change the tmp location from 
audacity-test 
to 
audacity 
then go into

/ var / tmp / audacity-username and create the same folder with the same name as the name in your audacity.cfg

Thank you