I downloaded audacity last night and it worked perfectly. I opened it this morning and it pops up saying “Audacity is already running” and it won’t open. Does anyone know how to help? Any help/advice will be greatly appreciated 
Is it Yosemite?
Try everything in https://forum.audacityteam.org/t/audacity-is-already-running-glitch/37328/1
If nothing there helps, please post the information requested in the final post ( https://forum.audacityteam.org/t/audacity-is-already-running-glitch/37328/13 ).
Gale
I’ve tried everything and it’s still not working 
What exactly did you try? Have you tried repairing the disk and repairing permissions?
Is it Yosemite or some other version of OS X? We can’t see your computer, so we have to ask.
Did you make system changes since last night, if so, what were those changes?
As requested please post the information about your system temporary directory: https://forum.audacityteam.org/t/audacity-is-already-running-glitch/37328/13 The Terminal is at /Applications/Utilities/Terminal.app.
Gale