Windows 2000 Group Policy Template File Format

In Microsoft Windows 2000, Group Policy administrative templates are stored using the .adm file format. This article explains the structure and function of the ADM file format in Windows 2000, how the operating system utilizes these files to enforce registry-based policies, and how they compare to modern Group Policy management standards.

The ADM File Format

The ADM (.adm) file extension stands for Administrative Template. In Windows 2000, these files are plain-text markup files that define the user interface displayed in the Group Policy Editor (gpedit.msc) and map policy settings directly to specific registry keys and values in the Windows registry.

When an administrator configures a policy setting under the Administrative Templates node, the Group Policy snap-in reads the instructions in the associated .adm file to present configurable options, explanations, and default values.

Structure and Syntax

ADM files use a proprietary, bracket-less markup syntax structured into hierarchical sections:

  • CLASS: Defines the scope of the settings, split into MACHINE (applying to HKEY_LOCAL_MACHINE) and USER (applying to HKEY_CURRENT_USER).
  • CATEGORY: Groups related policy settings together into display folders.
  • POLICY: Defines the specific configurable policy setting.
  • PART: Specifies the user interface controls inside the policy (such as checkboxes, text boxes, drop-down menus, or numeric spinners).
  • [STRINGS]: Located at the end of the file, this section holds the localizable text strings displayed in the administrative interface, keeping language strings distinct from registry logic within the same file.

Default ADM Files in Windows 2000

Windows 2000 includes several standard .adm files located in the %SystemRoot%\Inf directory:

  • System.adm: Contains operating system and core component settings for both users and computers.
  • Inetres.adm: Defines Internet Explorer settings and policies.
  • Conf.adm: Manages Microsoft NetMeeting options.
  • Wmplayer.adm: Houses policies for Windows Media Player.

When an administrator edits a Group Policy Object (GPO), the active .adm files are copied directly into the GPO's folder within the Active Directory SYSVOL share (SYSVOL\domain\Policies\{GUID}\Adm).

Limitations and Successors

While effective for Windows 2000, the .adm format had significant drawbacks, primarily GPO "bloat" caused by storing copies of the files in every GPO on the SYSVOL share, and the lack of multilingual separation. Microsoft addressed these limitations in Windows Vista and Windows Server 2008 by replacing the .adm format with the XML-based .admx (language-neutral settings) and .adml (language-specific resources) formats, backed by a centralized SYSVOL Central Store.