This document describes how to connect to theWindows Special Administrative Console (SAC).The SAC uses a serial port connection to a Windows virtual machine (VM) instanceand doesn't rely on network connectivity, which can help troubleshoot or recovera Windows VM instance. By connecting to the VM's serial console and using the SAC,you can interrupt the VM's boot process or gain access to a CMD or PowerShellterminal to perform troubleshooting. For a general purpose remote desktopexperience other than troubleshooting,connect to Windows VMs using RDP.

Before you begin

• Before you can connect to your VM's SAC by using the interactive serialconsole, enable interactive access for your VM. For more information, seeEnabling interactive access on the serial console.
• If you haven't already, set upauthentication. Authentication verifies your identity for access to Google Cloud services and APIs. To run code or samples from a local development environment, you can authenticate to Compute Engine by selecting one of the following options:

  Select the tab for how you plan to use the samples on this page:

  Console

  When you use the Google Cloud console to access Google Cloud services and APIs, you don't need to set up authentication.

  gcloud

  1. Install the Google Cloud CLI. After installation,initialize the Google Cloud CLI by running the following command:

     gcloudinit

     If you're using an external identity provider (IdP), you must first sign in to the gcloud CLI with your federated identity.

     Note: If you installed the gcloud CLI previously, make sure you have the latest version by runninggcloud components update.
  2. Set a default region and zone.

Computer is booting, SAC started and initialized.Use the "ch -?" command for information about using channels.Use the "?" command for general help.SAC>

gcloud compute connect-to-serial-portVM_NAME \    --port=2 \    --zone=ZONE \    --project=PROJECT_ID

Computer is booting, SAC started and initialized.Use the "ch -?" command for information about using channels.Use the "?" command for general help.SAC>

For information about using the interactive serial console, see the MicrosoftSAC Commands documentation.

Open Command Prompt in Windows SAC

To open Command Prompt in the SAC, do the following:

1. Typecmd, then pressEnter. You see the following output:

   SAC>cmdThe Command Prompt session was successfully launched.SAC>EVENT:   A new channel has been created.  Use "ch -?" for channel help.Channel: Cmd0001SAC>

2. Use thech -snCHANNEL_NAME command, then pressEnter.

   ch -snCHANNEL_NAME

   ReplaceCHANNEL_NAME with the name of thechannel you created in the previous step.

   The output is similar to the following:

   Name:                  Cmd0001Description:           CommandType:                  VT-UTF8Channel GUID:          28de7392-5413-11ea-bb03-c9656a2ed613Application Type GUID: 63d02271-8aa4-11d5-bccf-00b0d014a2d0Press <esc><tab> for next channel.Press <esc><tab>0 to return to the SAC channel.Use any other key to view this channel.

3. PressSpace, then login with the local credentials registered on thesystem.

   Please enter login credentials.Username:USERNAMEDomain:DOMAIN (leave blank if no domain)Password:PASSWORD

   Note: If you are unsure of the credentials, you might be able tocreate orreset the password.

   Once connected, you have access to a Command Prompt shell.

   Microsoft Windows [Version 10.0.14393](c) 2016 Microsoft Corporation. All rights reserved.C:\Windows\system32>

4. Optional: To enter a Powershell prompt, typepowershell.exe, then pressEnter.

   Note: Pasting into the SAC Powershell terminal might result in repeatedcharacters in the pasted text. You can prevent this on a per-session basis by issuing theRemove-Module PSReadLine command in your terminal.

What's next

• Learn how toconnect to Windows VMs using RDP
• Learn how totroubleshoot Interactive Serial Console.