Start docker daemon

I have been using Local for a while with no problems. Today when I tried to start Local it got to the list of WordPress sites screen but when I tried to start one of the sites I got an error saying:
"Error When Starting Site
Cannot connect to the Dock damon at unix//var/run/docker.sock. Is the docker daemon running? …’ then the ‘Checking System’ loading screen appears and Local tries and fails to fix itself.

How do I fix this? Do I have to start the Docker daemon manually or something?

Im using Mac OS Sierra 10.12