Where Regedit Stores Plug and Play Device Info

This article explains the exact Windows Registry location where the Plug and Play (PnP) manager stores hardware device parameters. It covers the primary registry key structure under HKEY_LOCAL_MACHINE, how device hierarchy is organized by hardware enumerators, and the specific subkeys that contain device-level configurations and driver properties.

The Primary Registry Location

The Windows Registry stores all hardware device parameters detected and managed by the Plug and Play subsystem under the following path:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum

The Enum key serves as the central database for all hardware device configurations, active buses, and connected components recognized by the operating system.

Registry Hierarchy and Structure

Within the Enum tree, hardware is organized in a strict multi-level hierarchy:

1. Enumerator (Bus Type): The top-level subkeys represent the hardware bus or subsystem enumerator responsible for discovering the device. Common examples include:

   • PCI – Peripheral Component Interconnect devices
   • USB – Universal Serial Bus devices
   • HID – Human Interface Devices
   • ACPI – Advanced Configuration and Power Interface devices
   • STORAGE – Mass storage devices

2. Device Identifier: Under each bus key, subkeys are named using vendor and device IDs (for example, VEN_10DE&DEV_1C03 for a specific PCI graphics card, or VID_046D&PID_C52B for a USB peripheral).

3. Instance Identifier: Under each device ID, individual subkeys represent the unique physical or logical instance of the device on the computer. This distinguishes multiple identical devices connected at the same time.

The Device Parameters Subkey

Inside a device’s specific instance key, PnP stores hardware settings in a dedicated subkey:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\<Enumerator>\<DeviceID>\<InstanceID>\Device Parameters

This subkey contains values written by the Plug and Play manager, bus drivers, and device installation packages. Typical values found here include:

• Hardware-specific configuration options
• Power management policies and idle states
• Interrupt allocation settings
• Port and interface assignments

Related Plug and Play Keys

In addition to the Enum branch, PnP references two other critical keys in CurrentControlSet:

• Device Class GUIDs: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class links devices to their broad functional categories (such as Display Adapters or Network Interfaces) and stores upper/lower filter drivers.
• Driver Services: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services contains configuration and startup parameters for the driver binaries loaded for each PnP device.

Access Permissions

The Enum branch is strictly protected by Windows system security. The operating system assigns SYSTEM and TrustedInstaller ownership to these keys. Standard administrators have Read permissions by default, preventing accidental modification of critical Plug and Play state data while the system is running.