What is Windows RE?
Windows Recovery Environment (Windows RE) is an extensible recovery platform based on Windows Preinstallation Environment (Windows PE). When the computer fails to start, Windows automatically fails over into this environment, and the Startup Repair tool in Windows RE automates the diagnosis and repair of an unbootable Windows Vista® installation. Furthermore, Windows RE is a starting point for various tools for manual system recovery. The primary audience of this technology includes original equipment manufacturers (OEMs), original device manufacturers (ODMs), and corporate IT professionals.
This topic includes:
- Benefits of Windows RE
- Common scenarios
- Image-based recovery from Windows RE
- Security considerations
- Technologies related to Windows RE
Benefits of Windows RE
Windows RE provides the following benefits:
- Can help reduce support costs by up to 80 percent through automatic repair of common root causes of unbootable operating system installations.
- Can add customized recovery tools to Windows RE.
- Can be used as the platform for image recovery.
- Supports mass-storage drivers and language packs through Windows PE tools.
- Can run automatically or manually.
- Provides diagnostic and repair logs.
Common Scenarios
End-user Scenario
A home user installs a video card driver from Fabrikam and restarts his computer. While Windows Vista restarts, the computer stops unexpectedly and an error message appears on a blue screen because of the driver. The computer automatically restarts. The user then sees a message that the computer failed to start and that Windows will attempt to repair it. Once in Windows RE, the Startup Repair wizard actively diagnoses the computer and determines that System Restore must repair the problematic video card driver. The user chooses to repair the video card driver, and the computer restarts after the repair. Now the computer successfully restarts, and the user sees the logon screen for Windows.
System Administrator Scenario
A system administrator for an enterprise is attempting to fix a client computer that cannot start. The administrator presses F8 during startup and selects the Recovery Environment entry, which boots the computer into Windows RE. He logs on by using a local administrator account, and selects the full-volume restore application from the list of available tools. Once the restore has completed, the administrator clicks the Reset button in Windows RE, and the computer restarts.
Unsupported Scenario
A user attempts to log on to their Windows user account by typing their password. However, the computer encounters a problem and crashes, triggering a restart. The computer restarts to Windows Vista without failing over into Windows RE. The user is back at the logon screen, and the error in Windows Vista is not repaired automatically.
Image-based Recovery from Windows RE
In the event that the Windows installation cannot be repaired with Startup Repair or other manual repair steps, Windows RE can be used to launch an image-based recovery tool.
User-created Recovery Image
Windows Vista provides end users with the ability to create a backup image of their entire operating system. End users can do this by using the Backup tool. The system image can be stored on an external hard disk, on a hard disk partition other than those imaged, or on a DVD. To restore the computer by using this system image, users must launch the restore interface from the list of Windows RE manual tools.
Factory-created Recovery Image
To facilitate restoring a computer to its factory state, a recovery image can be placed on the Windows RE partition. This eliminates the need for a separate recovery media in most cases.
If the Windows image format is used in the manufacturing process, the same operating system image can be used for recovery as well. A computer manufacturer can develop an application by using the Imaging APIs for Windows and the Windows image to restore the operating system volume. This application can be launched from the Windows RE user interface (UI) by using customizations provided by the ODM.
Security Considerations
When working with Windows RE, keep in mind the following security considerations:
- When launching Windows RE from hard disk by using the F8 advanced boot options screen, users are required to use a local user name and password for authentication. To gain access to the Command Prompt window, the built-in administrator account must be used. Any local user can gain access to tools such as System Restore and the customized recovery application from the list of manual tools.
- By default, networking is turned off in Windows RE. Applications can turn on networking dynamically if needed but are advised to disable it when network connectivity is no longer needed.
- Because Windows RE does not include the security infrastructure present in the Windows Vista operating system, manufacturers and system administrators should not install Windows RE on hard disks of high-security risk computers, such as public kiosk computers running Windows Vista.
Technologies Related to Windows RE
Windows RE is related to the following technologies:
Windows Preinstallation Environment (Windows PE)
Windows Preinstallation Environment (Windows PE) is a minimal Win32 operating system with limited services. Windows RE is built from Windows PE.
ImageX
ImageX is a command-line tool that enables the capture, the modification, and the application of file-based Windows images for rapid deployment. Windows RE is a customized Windows PE image (.wim) file that can be modified only by using ImageX. Windows RE scripts also rely on ImageX to install Windows RE images.