Process.Start Method (String, String, String, SecureString, String)

Starts a process resource by specifying the name of an application, a set of command-line arguments, a user name, a password, and a domain and associates the resource with a new Process component.

Namespace: System.Diagnostics
Assembly: System (in system.dll)

public static Process Start (
	string fileName,
	string arguments,
	string userName,
	SecureString password,
	string domain
public static Process Start (
	String fileName, 
	String arguments, 
	String userName, 
	SecureString password, 
	String domain
public static function Start (
	fileName : String, 
	arguments : String, 
	userName : String, 
	password : SecureString, 
	domain : String
) : Process
Not applicable.



The name of an application file to run in the process.


Command-line arguments to pass when starting the process.


The user name to use when starting the process.


A SecureString that contains the password to use when starting the process.


The domain to use when starting the process.

Return Value

A new Process component that is associated with the process resource, or a null reference (Nothing in Visual Basic) if no process resource is started (for example, if an existing process is reused).

Exception typeCondition


No file name was specified.


fileName is not an executable (.exe) file.


There was an error in opening the associated file.


The process object has already been disposed.

Use this overload to create a new process and its primary thread by specifying its file name, command-line arguments, user name, password, and domain. The new process then runs the specified executable file in the security context of the specified credentials (user, domain, and password).


When the executable file is located on a remote drive, you must identify the network share by using a uniform resource identifier (URI), not a linked drive letter.

The overload associates the resource with a new Process component. If the process is already running, no additional process resource is started. Instead, the existing process resource is reused and no new Process component is created. In such a case, instead of returning a new Process component, Start returns a null reference (Nothing in Visual Basic) to the calling procedure.

This overload lets you start a process without first creating a new Process instance. The overload is an alternative to the explicit steps of creating a new Process instance, setting the FileName, Arguments, UserName, Password, and Domain properties of the StartInfo property, and calling Start for the Process instance.

Similarly, in the same way that the Run dialog box can accept an executable file name with or without the .exe extension, the .exe extension is optional in the fileName parameter. For example, you can set the fileName parameter to either "Notepad.exe" or "Notepad". If the fileName parameter represents an executable file, the arguments parameter might represent a file to act upon, such as the text file in Notepad.exe myfile.txt.


The file name must represent an executable file in the Start overloads that have userName, password, and domain parameters.

  • LinkDemand  for full trust for the immediate caller. This member cannot be used by partially trusted code.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0

Community Additions