How do we start the daemon?

If you're using Docker for Windows, Then simply start the desktop app installed in C:\Program Files\Docker\Docker\Docker Desktop.exe

You can also stop Docker for Windows and run just the Docker daemon dockerd.exe. That'll only let you run Docker Windows Containers. dockerd.exe is in the program files directory.

If you have installed docker on Windows 10 Pro with Hyper-V enabled and still you are not able to run Docker on Windows 10, then as the error suggests that your docker daemon is not started. Follow following steps it helped me to start docker successfully

1. Use command on CMD(Admin mode) docker-machine restart default then you will get msg like "open C:\User{User_name}.docker\machine\machines\default\config.json: The system cannot find the file specified."
   Go to the docker icon which will be on your windows tray(Right corner of the desktop). Then Right click on the docker icon -> setting-> Reset -> Restart Docker It will take few moments then you will see the message "Docker is running with the green indicator".
   Note- If you have already had running Docker containers running on your system then don't follow these steps. You may lose the exiting containers.