using System.Management;
...
        public static string? GetProcessOwner(int processId)
        {
            string? MethodResult = null;
            try
            {
                string Query = $"SELECT * FROM WIN32_PROCESS WHERE ProcessId = {processId}";

                ManagementObjectCollection Processes = new ManagementObjectSearcher(Query).Get();

                foreach (ManagementObject Process in Processes.Cast<ManagementObject>())
                {
                    string[] Args = ["", ""];

                    int ReturnCode = Convert.ToInt32(Process.InvokeMethod("GetOwner", Args));

                    MethodResult = ReturnCode switch
                    {
                        0 => Args[1] + "\\" + Args[0],
                        _ => "NONE",
                    };
                }

            }
            catch (Exception ex)
            {
                MessageBox.Show($"Error geting process owner: \n{ex.Message}");
            }
            return MethodResult;
        }

using System.Management;
...
        public static string? GetProcessOwner(int processId)
        {
            string? MethodResult = null;
            try
            {
                string Query = $"SELECT * FROM WIN32_PROCESS WHERE ProcessId = {processId}";

                ManagementObjectCollection Processes = new ManagementObjectSearcher(Query).Get();

                foreach (ManagementObject Process in Processes.Cast<ManagementObject>())
                {
                    string[] Args = ["", ""];

                    int ReturnCode = Convert.ToInt32(Process.InvokeMethod("GetOwner", Args));

                    MethodResult = ReturnCode switch
                    {
                        0 => Args[1] + "\\" + Args[0],
                        _ => "NONE",
                    };
                }

            }
            catch (Exception ex)
            {
                MessageBox.Show($"Error geting process owner: \n{ex.Message}");
            }
            return MethodResult;
        }