Restart-Computer

Restarts the operating system on local and remote computers.

Syntax

Restart-Computer
       [-DcomAuthentication <AuthenticationLevel>]
       [-Impersonation <ImpersonationLevel>]
       [-WsmanAuthentication <String>]
       [-Protocol <String>]
       [[-ComputerName] <String[]>]
       [[-Credential] <PSCredential>]
       [-Force]
       [-Wait]
       [-Timeout <Int32>]
       [-For <WaitForServiceTypes>]
       [-Delay <Int16>]
       [-WhatIf]
       [-Confirm]
       [<CommonParameters>]
Restart-Computer
       [-AsJob]
       [-DcomAuthentication <AuthenticationLevel>]
       [-Impersonation <ImpersonationLevel>]
       [[-ComputerName] <String[]>]
       [[-Credential] <PSCredential>]
       [-Force]
       [-ThrottleLimit <Int32>]
       [-WhatIf]
       [-Confirm]
       [<CommonParameters>]

Description

The Restart-Computer cmdlet restarts the operating system on the local and remote computers.

You can use the parameters of Restart-Computer to run the restart operations as a background job, to specify the authentication levels and alternate credentials, to limit the operations that run at the same time, and to force an immediate restart.

Starting in Windows PowerShell 3.0, you can wait for the restart to complete before you run the next command. Specify a waiting time-out and query interval, and wait for particular services to be available on the restarted computer. This feature makes it practical to use Restart-Computer in scripts and functions.

You can use the WS-Management (WSMan) protocol to restart the computer, in case Distributed Component Object Model (DCOM) calls are blocked, such as by an enterprise firewall. For more information, see WS-Management Protocol.

This cmdlet requires Windows PowerShell remoting only when you use the AsJob parameter in a command.

Examples

Example 1: Restart the local computer

Restart-Computer restarts the local computer.

Restart-Computer

Example 2: Restart multiple computers

Restart-Computer can restart remote and local computers. The ComputerName parameter accepts an array of computer names.

Restart-Computer -ComputerName Server01, Server02, localhost

Example 3: Restart computers as a background job

These commands run a Restart-Computer command as a background job on two remote computers, and then get the results.

Because AsJob creates the job on the local computer and automatically returns the results to the local computer, you can run Receive-Job as a local command.

$Job = Restart-Computer -ComputerName "Server01", "Server02" -AsJob
$Job | Receive-Job

Restart-Computer uses the ComputerName parameter to specify Server01 and Server02. The AsJob parameter runs the command as a background job. The job object is stored in the $Job variable. $Job is sent down the pipeline to the Receive-Job cmdlet that gets the results.

Example 4: Restart a remote computer

Restart-Computer restarts a remote computer with customized impersonation and authentication settings.

Restart-Computer -ComputerName Server01 -Impersonation Anonymous -DcomAuthentication PacketIntegrity

Restart-Computer uses the ComputerName parameter to specify Server01. The Impersonation parameter specifies Anonymous to hide the requester's identity. The DcomAuthentication parameter specifies PacketIntegrity as the connection's authentication level.

Example 5: Force restart of computers listed in a text file

This example forces an immediate restart of the computers listed in the Domain01.txt file. The computer names from the text file are stored in a variable. The Force parameter forces an immediate restart and the ThrottleLimit parameter limits the number of concurrent connections.

$Names = Get-Content -Path C:\Domain01.txt
$Creds = Get-Credential
Restart-Computer -ComputerName $Names -Credential $Creds -Force -ThrottleLimit 10

Get-Content uses the Path parameter to get a list of computer names from a text file, Domain01.txt. The computer names are stored in the variable $Names. Get-Credential prompts you for a username and password and stores the values in the variable $Creds. Restart-Computer uses the ComputerName and Credential parameters with their variables. The Force parameter causes an immediate restart of each computer. The ThrottleLimit parameter limits the command to 10 concurrent connections.

Example 6: Restart a remote computer and wait for PowerShell

Restart-Computer restarts the remote computer and then waits up to 5 minutes (300 seconds) for PowerShell to become available on the restarted computer before it continues.

Restart-Computer -ComputerName Server01 -Wait -For PowerShell -Timeout 300 -Delay 2

Restart-Computer uses the ComputerName parameter to specify Server01. The Wait parameter waits for the restart to finish. The For specifies that PowerShell can run commands on the remote computer. The Timeout parameter specifies a five-minute wait. The Delay parameter queries the remote computer every two seconds to determine whether it's restarted.

Example 7: Restart a computer by using the WSMan Protocol

Restart-Computer restarts the remote computer by using the WSMan protocol instead of the default, DCOM. Kerberos authentication determines whether the current user has permission to restart the remote computer.

These settings are designed for enterprises in which DCOM-based restarts fail because DCOM is blocked. For example, by a firewall.

Restart-Computer -ComputerName Server01 -Protocol WSMan -WsmanAuthentication Kerberos

Restart-Computer uses the ComputerName parameter to specify the remote computer, Server01. The Protocol parameter specifies to use the WSMan protocol. The WsmanAuthentication parameter specifies the authentication method as Kerberos.

Parameters

-AsJob

Indicates that Restart-Computer runs as a background job.

To use this parameter, the local and remote computers must be configured for remoting. On Windows Vista and later versions of the Windows operating system, you must open PowerShell by using the Run as Administrator option. For more information, see about_Remote_Requirements.

When you specify the AsJob parameter, the command immediately returns an object that represents the background job. You can continue to work in the session while the job finishes. The job is created on the local computer and the results from remote computers are automatically returned to the local computer. To manage the job, use the Job cmdlets. To get the job results, use the Receive-Job cmdlet.

For more information about Windows PowerShell background jobs, see about_Jobs and about_Remote_Jobs.

Type:SwitchParameter
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-ComputerName

Specifies one computer name or a comma-separated array of computer names. Restart-Computer accepts ComputerName objects from the pipeline or variables.

Type the NetBIOS name, an IP address, or a fully qualified domain name of a remote computer. To specify the local computer, type the computer name, a dot ., or localhost.

This parameter doesn't rely on PowerShell remoting. You can use the ComputerName parameter even if your computer isn't configured to run remote commands.

If the ComputerName parameter isn't specified, Restart-Computer restarts the local computer.

Type:String[]
Aliases:CN, __SERVER, Server, IPAddress
Position:0
Default value:None
Accept pipeline input:True (ByPropertyName, ByValue)
Accept wildcard characters:False
-Confirm

Prompts you for confirmation before running Restart-Computer.

Type:SwitchParameter
Aliases:cf
Position:Named
Default value:False
Accept pipeline input:False
Accept wildcard characters:False
-Credential

Specifies a user account that has permission to do this action. The default is the current user.

Type a user name, such as User01 or Domain01\User01, or enter a PSCredential object generated by the Get-Credential cmdlet. If you type a user name, you're prompted to enter the password.

Credentials are stored in a PSCredential object and the password is stored as a SecureString.

Note

For more information about SecureString data protection, see How secure is SecureString?.

Type:PSCredential
Position:1
Default value:Current user
Accept pipeline input:False
Accept wildcard characters:False
-DcomAuthentication

Specifies the authentication level that is used for the WMI connection. Restart-Computer uses WMI.

Valid values are:

  • Call: Call-level COM authentication
  • Connect: Connect-level COM authentication
  • Default: Windows Authentication
  • None: No COM authentication
  • Packet: Packet-level COM authentication.
  • PacketIntegrity: Packet Integrity-level COM authentication
  • PacketPrivacy: Packet Privacy-level COM authentication.
  • Unchanged: The authentication level is the same as the previous command.

For more information, see AuthenticationLevel Enumeration.

This parameter is introduced in Windows PowerShell 3.0.

Type:AuthenticationLevel
Aliases:Authentication
Accepted values:Default, None, Connect, Call, Packet, PacketIntegrity, PacketPrivacy, Unchanged
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Delay

Specifies the frequency of queries, in seconds. PowerShell queries the service specified by the For parameter to determine whether the service is available after the computer is restarted.

This parameter is valid only together with the Wait and For parameters.

This parameter was introduced in Windows PowerShell 3.0.

If the Delay parameter isn't specified, Restart-Computer uses a five second delay.

Type:Int16
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-For

Specifies the behavior of PowerShell as it waits for the specified service or feature to become available after the computer restarts. This parameter is only valid with the Wait parameter.

The acceptable values for this parameter are:

  • Default: Waits for PowerShell to restart.
  • PowerShell: Can run commands in a PowerShell remote session on the computer.
  • WMI: Receives a reply to a Win32_ComputerSystem query for the computer.
  • WinRM: Can establish a remote session to the computer by using WS-Management.

This parameter was introduced in Windows PowerShell 3.0.

Type:WaitForServiceTypes
Accepted values:Wmi, WinRM, PowerShell
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Force

Forces an immediate restart of the computer.

Type:SwitchParameter
Aliases:f
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Impersonation

Specifies the impersonation level that this cmdlet uses to call WMI. Restart-Computer uses WMI. The acceptable values for this parameter are:

  • Default: Default impersonation. Despite the name, this isn't the default value.
  • Anonymous: Hides the identity of the caller.
  • Identify: Allows objects to query the credentials of the caller.
  • Impersonate: Allows objects to use the credentials of the caller.
Type:ImpersonationLevel
Accepted values:Default, Anonymous, Identify, Impersonate, Delegate
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Protocol

Specifies which protocol to use to restart the computers. The valid values are WSMan and DCOM.

This parameter is introduced in Windows PowerShell 3.0.

Type:String
Accepted values:DCOM, WSMan
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-ThrottleLimit

Specifies the maximum number of concurrent connections that can be established to run this command. The throttle limit applies only to the current command, not to the session or to the computer.

If the ThrottleLimit parameter isn't specified or a value of 0 is used, Restart-Computer uses a maximum of 32 concurrent connections.

Type:Int32
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Timeout

Specifies the duration of the wait, in seconds. When the timeout elapses, Restart-Computer returns to the command prompt, even if the computers aren't restarted.

The Timeout parameter is only valid with the Wait parameter. Timeout overrides the Wait parameter's indefinite waiting period.

This parameter was introduced in Windows PowerShell 3.0.

Type:Int32
Aliases:TimeoutSec
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-Wait

Restart-Computer suppresses the PowerShell prompt and blocks the pipeline until the computers have restarted. You can use this parameter in a script to restart computers and then continue to process when the restart is finished.

The Wait parameter waits indefinitely for the computers to restart. You can use Timeout to adjust the timing and the For and Delay parameters to wait for particular services to become available on the restarted computers.

The Wait parameter isn't valid when you're restarting the local computer. If the value of the ComputerName parameter contains the names of remote computers and the local computer, Restart-Computer generates a non-terminating error for Wait on the local computer, but waits for the remote computers to restart.

This parameter was introduced in Windows PowerShell 3.0.

Type:SwitchParameter
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False
-WhatIf

Shows what would happen if the Restart-Computer runs. The Restart-Computer cmdlet isn't run.

Type:SwitchParameter
Aliases:wi
Position:Named
Default value:False
Accept pipeline input:False
Accept wildcard characters:False
-WsmanAuthentication

Specifies the mechanism that is used to authenticate the user credentials. This parameter was introduced in Windows PowerShell 3.0.

The acceptable values for this parameter are: Basic, CredSSP, Default, Digest, Kerberos, and Negotiate.

For more information, see AuthenticationMechanism.

Warning

Credential Security Service Provider (CredSSP) authentication, in which the user credentials are passed to a remote computer to be authenticated, is designed for commands that require authentication on more than one resource, such as accessing a remote network share. This mechanism increases the security risk of the remote operation. If the remote computer is compromised, the credentials that are passed to it can be used to control the network session.

Type:String
Accepted values:Basic, CredSSP, Default, Digest, Kerberos, Negotiate
Position:Named
Default value:None
Accept pipeline input:False
Accept wildcard characters:False

Inputs

System.String

Restart-Computer accepts computer names from the pipeline or variables.

In Windows PowerShell 2.0, the ComputerName parameter takes input from the pipeline only by property name. In Windows PowerShell 3.0, and later, the ComputerName parameter takes input from the pipeline by value.

Outputs

None, System.Management.Automation.RemotingJob

If you specify the AsJob parameter, Restart-Computer returns a job object. Otherwise, no output is generated.

Notes

  • Restart-Computer only work on computers running Windows and requires WinRM and WMI to shutdown a system, including the local system.
  • Restart-Computer uses the Win32Shutdown method of the Windows Management Instrumentation (WMI) Win32_OperatingSystem class.

In Windows PowerShell 2.0, the AsJob parameter doesn't work reliably when you are restarting or stopping remote computers. In Windows PowerShell 3.0, the implementation is changed to resolve this problem.