Question: When I am starting rails server using `rails s` command it is showing `A server is already running. Check C:/Sites/folder/Pids/Server.pids`

When I open the file it is outputting a 4 digit number only so how could I resolve this issue ? 

**FYI**

1. No other instance of Rails cmd is running this time.
2. Checked Task manager but only `cmd.exe` is showing no else process is running. (using Windows).

Answer: 
**TL;DR Just Run this command to Kill it**

```
sudo kill -9 $(lsof -i :3000 -t)

```

**Root Cause:**
Because PID is locked in a file and web server thinks that if that file exists then it means it is already running. Normally when a web server is closed that file is deleted, but in some cases, proper deletion doesn't happen so you have to remove the file manually
**New Solutions** 

when you run **rails s**

=> Booting WEBrick

=> Rails 4.0.4 application starting in development on `http://0.0.0.0:3000`

=> Run `rails server -h` for more startup options

=> Ctrl-C to shutdown server

**A server is already running. Check /your\_project\_path/tmp/pids/server.pid.**
Exiting

So place your path shown here /your\_project\_path/tmp/pids/server.pid 

and remove this **server.pid** file:

```
rm /your_project_path/tmp/pids/server.pid

```

**OR Incase you're server was detached then follow below guidelines:**

If you detached you rails server by using command "rails -d" then,

Remove rails detached server by using command 

```
ps -aef | grep rails

```

**OR by this command**

```
sudo lsof -wni tcp:3000

```

then

```
kill -9 pID

```

**OR use this command**

To find and kill process by port name on which that program is running. For 3000 replace port on which your program is running.

```
sudo kill -9 $(lsof -i :3000 -t)

```

**Old Solution:**

```
rails s -p 4000 -P tmp/pids/server2.pid

```

Also you can find this post for more options
[Rails Update to 3.2.11 breaks running multiple servers](https://stackoverflow.com/questions/14329370/rails-update-to-3-2-11-breaks-running-multiple-servers)
It happens when you kill your server process and the pid file was not updated.
The best solution is to delete the file **Server.pid**.

Use the command 

> 
> `rm <path to file Server.pid>`
> 
> 
>