Question: Running

```
$ mpd

```

I am prompted with

> 
> socket: Failed to bind to '127.0.0.1:6600': Address already in use
> 
> 
> 

But if I run:

```
 $ sudo service mpd start

```

and check its status, I get

> 
> systemd[1]: Started Music Player Daemon.
> 
> 
> 

Note that in what is to come, assume that:

```
 $ sudo service mpd stop

```

has been run.

### Questions

* What is the difference between the two, why does one give an error, and the other not?
* How can I track/find how the socket is being used? As mentioned, first we stop the service, if it is running?

```
$ sudo service mpd stop

```

I search over stackexchange, and the solutions mentioned don't find anything.

```
$ sudo lsof -i -n -P|grep 6600 

```

returns nothing

```
$ sudo netstat -tulpn |grep 6600 

```

return nothing

```
$ sudo ss -npt|grep 6600

```

return nothing. But, again,

```
$ mpd

```

returns

> 
> socket: Failed to bind to '127.0.0.1:6600': Address already in use
> 
> 
> 

What do I not understand?

Answer: 
It looks like you are using Systemd 

As [mentioned in the comments](https://unix.stackexchange.com/questions/456909/socket-already-in-use-but-is-not-listed-mpd#comment830215_456909) you also need to stop the socket

```bsh
sudo systemctl stop mpd.socket

```
It might be a bit late but I had the same problem and setting bind\_to\_address in mpd.conf file to "0.0.0.0" seemed to fix it.

Also there is a good explanation of why that might be happening [here](https://stackoverflow.com/a/5106755/6321322)