Start Method (String, String, String, SecureString, String)

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


Type: System.String

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

Type: System.String

Command-line arguments to pass when starting the process.

Type: System.String

The user name to use when starting the process.

Type: System.Security.SecureString

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

Type: System.String

The domain to use when starting the process.

Return Value

Type: System.Diagnostics.Process

A new Process that is associated with the process resource, or null if no process resource is started. Note that a new process that’s started alongside already running instances of the same process will be independent from the others. In addition, Start may return a non-null Process with its HasExited property already set to true. In this case, the started process may have activated an existing instance of itself and then exited.

Exception Condition

No file name was specified.


fileName is not an executable (.exe) file.


An error occurred when opening the associated file.


The sum of the length of the arguments and the length of the full path to the associated file exceeds 2080. The error message associated with this exception can be one of the following: "The data area passed to a system call is too small." or "Access is denied."


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.


If the address of the executable file to start is a URL, the process is not started and null is returned.

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.

Whenever you use Start to start a process, you might need to close it or you risk losing system resources. Close processes using CloseMainWindow or Kill. You can check whether a process has already been closed by using its HasExited property..


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

.NET Framework
Available since 2.0
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