Windows 2000 Unattended Setup via UNATTEND.TXT

Microsoft Windows 2000 enables hands-free operating system deployment through scripted installations that use an answer file, typically named UNATTEND.TXT. This article explains how the Windows 2000 Setup engine interprets this file to bypass manual installation prompts, the command-line switches required to initiate the process, and the two-phase installation workflow that transforms text entries into a fully configured system.

The Purpose of UNATTEND.TXT

UNATTEND.TXT is an INI-style configuration script containing predefined responses to the queries presented during installation. The file is divided into distinct sections, including:

  • [Unattended]: Defines automation behavior, file system conversion (e.g., converting to NTFS), and driver detection options.
  • [UserData]: Supplies user-specific information such as the Product Key, Organization Name, Computer Name, and Full Name.
  • [GuiUnattended]: Configures regional settings, the local Administrator password, and time zones.
  • [Identification]: Specifies network participation, joining the target machine to a Workgroup or Windows 2000 Active Directory Domain.
  • [Networking]: Configures network adapters, TCP/IP parameters, and protocol bindings.

To achieve complete automation, the directive UnattendMode = FullUnattended is specified under the [Unattended] section. This forces Setup to suppress all interactive wizard dialogues and halt with an error if required configuration data is missing.

Initiating Setup

The execution method depends on the environment from which Setup is launched:

1. 16-Bit MS-DOS Environment (winnt.exe)

When deploying to bare-metal systems booted from a DOS diskette or network share, the 16-bit installer is executed with the /u and /s switches:

winnt.exe /s:Z:\i386 /u:Z:\i386\unattend.txt
  • /s: Points to the source files in the I386 directory.
  • /u: Designates the path to the unattended answer file.

2. 32-Bit Windows Environment (winnt32.exe)

When upgrading or performing a clean install from an existing 32-bit Windows system, winnt32.exe is used:

winnt32.exe /s:D:\i386 /unattend:D:\i386\unattend.txt /syspart:C:
  • /unattend: Triggers unattended mode and reads the specified script.

3. Bootable Media (WINNT.SIF)

If booting directly from a Windows 2000 CD-ROM or Preboot Execution Environment (PXE), Setup searches the I386 folder for an answer file named WINNT.SIF. This file uses the same syntax as UNATTEND.TXT but is processed automatically by the CD boot loader without requiring command-line arguments.

The Execution Workflow

Once executed, Windows 2000 processes the installation in two sequential stages:

Phase 1: Text-Mode Setup

  1. File Parsing: The text-mode installer initializes hardware drivers, reads UNATTEND.TXT, and parses the [Unattended] section.
  2. Disk Operations: Based on parameters like FileSystem = ConvertNTFS and Repartition = Yes, the setup engine formats the destination volume automatically.
  3. File Staging: Setup copies the core operating system files into a temporary directory ($WIN_NT$.~LS or $WIN_NT$.~BT) alongside a temporary copy of the answer file (saved as WINNT.SIF).
  4. Reboot: The machine automatically restarts into the Graphical User Interface (GUI) phase.

Phase 2: GUI-Mode Setup

  1. Mini-Setup Launch: Upon booting into protected mode, the GUI Setup engine reads the cached answer file.
  2. Configuration Injection: Setup applies network settings, imports the Product Key, establishes the local administrator password, and configures peripheral hardware using the values defined in the answer file.
  3. Command Execution: If an [OEMRunOnce] or [GuiRunOnce] section is present, the installer executes custom post-installation scripts or software deployments upon the first administrative logon.
  4. Finalization: Temporary installation directories are removed, and the system reboots into a fully configured, production-ready Windows 2000 environment.