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: 
On Windows Rails 5.2, delete this file

```
c:/Sites/<your_folder>/tmp/pids/server.pid

```

and run

```
rails s

```

again.
**Run:** `fuser -k -n tcp 3000`

This will kill the process running at the default port 3000.