Tutorial Windows – Kill a process using the command-line [ Step by step ]

I have Angular 8 installed on the server which uses port 4200. But today I can’t run angular on port 4200. The error message is “An unhandled exception occurred: listen EACCES: permission denied 127.0.0.1:4200”.

Using netstat -a I noticed that the port is listening and it is used by the system.
I tried to kill the process taskkill /F /PID 1242 but couldn’t. The error message is “Access is denied”.

How can I kill the process?

I have the following problem:
I try to Kill a Process of a Online Game from c# code. I always get “access denied”! It has an Anti Hack Shield, I think that’s the problem…

[Edit]
I added /T to the TaskKill Commandline and get now the Error child Process with PID “access denied”.
I can not find this PID neither in Process.GetProcessById() nor in the Threads List of the Main Process.. Someone know how to Find this?

But with the Window Task Manager I can kill it!
I get my Process by finding the Window with P/invoke FindWindow() and GetWindowThreadProcessId()
I checked the PID it is the same!
I use the P/Invoke because I need it anyway for SetFourgroundWindow()

I also found this active in kernel mode[1] it’s an online game so its using the network adapter, can this be the problem? but why I can kill it with Task manager?
In this case I find the SetKernelObjectSecurity: http://csharptest.net/coding/ I’m not sure if I did it right I just changed AceQualifier.AccessDenied to AccessAllowed not working.

So how can I Kill it the same way as the Task Manager do?
Or can I call the Method of the Task Manager?
Maybe I need to change some Parameter/ Rights before?

I searched and I find something with SeDebugPrivilege: [2] I used it but still the same “access denied” I also tried it with Process.EnterDebugMode();

That’s my ways I tried: I run Visual Studio as administrator

public void KillKal(IntPtr _WindowPointer)
{
    uint ProcessID;

    GetWindowThreadProcessId(_WindowPointer, out ProcessID);
    try
    {
        #region SeDebugPrivilege 
        IntPtr hToken;
        LUID luidSEDebugNameValue;
        TOKEN_PRIVILEGES tkpPrivileges;

        if (!OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, out hToken))
        {
            Console.WriteLine("OpenProcessToken() failed, error = {0} . SeDebugPrivilege is not available", Marshal.GetLastWin32Error());
            return;
        }
        else
        {
            Console.WriteLine("OpenProcessToken() successfully");
        }

        if (!LookupPrivilegeValue(null, SE_DEBUG_NAME, out luidSEDebugNameValue))
        {
            Console.WriteLine("LookupPrivilegeValue() failed, error = {0} .SeDebugPrivilege is not available", Marshal.GetLastWin32Error());
            CloseHandle(hToken);
            return;
        }
        else
        {
            Console.WriteLine("LookupPrivilegeValue() successfully");
        }

        tkpPrivileges.PrivilegeCount = 1;
        tkpPrivileges.Luid = luidSEDebugNameValue;
        tkpPrivileges.Attributes = SE_PRIVILEGE_ENABLED;

        if (!AdjustTokenPrivileges(hToken, false, ref tkpPrivileges, 0, IntPtr.Zero, IntPtr.Zero))
        {
            Console.WriteLine("LookupPrivilegeValue() failed, error = {0} .SeDebugPrivilege is not available", Marshal.GetLastWin32Error());
        }
        else
        {
            Console.WriteLine("SeDebugPrivilege is now available");
        }

        Process.EnterDebugMode();
        #endregion SeDebugPrivilege
        Process p = Process.GetProcessById((int)ProcessID);

        //1. try
        Process.Start(new ProcessStartInfo
        {
            FileName = "cmd.exe",
            CreateNoWindow = true,
            UseShellExecute = false,
            Verb = "runas",
            Arguments = string.Format("/c taskkill /pid {0} /f", ProcessID)
        });
        //2.try
        Process.Start(new ProcessStartInfo
        {
            FileName = "net.exe",
            CreateNoWindow = true,
            UseShellExecute = false,
            Verb = "runas",
            Arguments = string.Format("stop {0}", p.ProcessName)
        });
        //3. try
        Process.Start("cmd", string.Format("/c "taskkill /f /pid {0}"", ProcessID));

        //4. try get exception: access denided
        p.Kill();

        //5. try get exception:Process must exit before requested information can be determined.
        TerminateProcess(p.Handle, (uint)p.ExitCode);
    }
    catch (Exception e)
    {
        MessageBox.Show(e.ToString());
    }
}

I also tried with PsKill and task kill in administration cmd ! https://postimg.org/image/qp5nkjvtn/