Skip to main content

How to Access the 32-bit Registry from a 64-bit Script

On a 64-bit version of Windows, the operating system maintains two separate views of the registry to support both 64-bit and 32-bit applications. This is part of the WoW64 (Windows on Windows 64-bit) compatibility layer. When a 32-bit program tries to access a key like HKEY_LOCAL_MACHINE\Software, Windows transparently redirects it to a special location: HKEY_LOCAL_MACHINE\Software\Wow6432Node.

By default, a standard 64-bit batch script will only see the 64-bit view of the registry. This creates a problem: how do you read or write a registry key for a 32-bit application from your 64-bit script? The solution is to use a special switch in the built-in REG.EXE command.

The Core Concept: Registry Redirection and the Wow6432Node​

On a 64-bit OS:

  • 64-bit applications read and write to HKEY_LOCAL_MACHINE\Software.
  • 32-bit applications think they are reading and writing to HKEY_LOCAL_MACHINE\Software, but Windows silently redirects them to HKEY_LOCAL_MACHINE\Software\Wow6432Node.

A standard 64-bit cmd.exe process will not see the 32-bit keys unless it specifically asks to.

The Core Command: REG.EXE /reg:32​

The standard REG.EXE utility has a command-line switch that allows you to specify which "view" of the registry you want to access.

Syntax: REG <operation> <KeyName> ... /reg:32

  • /reg:32: This is the crucial switch. It tells the REG command to operate on the 32-bit view of the registry.
  • /reg:64: Can be used to explicitly specify the 64-bit view (this is the default).

This command requires administrator privileges if you are accessing the HKEY_LOCAL_MACHINE (HKLM) hive.

An Alternative Method: Calling the 32-bit reg.exe​

A 64-bit Windows system has two versions of reg.exe. You can force a 32-bit operation by calling the 32-bit version directly from its location in the SysWOW64 folder.

Syntax: %windir%\SysWOW64\reg.exe <operation> <KeyName> ...

This method is less explicit than using the /reg:32 switch but achieves the same result. The /reg:32 switch is generally the recommended modern approach.

Basic Example: Querying a 32-bit Application's Key​

Let's assume you have the 32-bit version of 7-Zip installed. Its uninstall information is stored in the 32-bit part of the registry.

@ECHO OFF
SET "RegKey=HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\7-Zip"

ECHO --- Accessing the Registry ---
ECHO.
ECHO Attempting to read with the default (64-bit) command...
REG QUERY "%RegKey%" /v DisplayName
ECHO.

ECHO Attempting to read with the /reg:32 switch...
REG QUERY "%RegKey%" /v DisplayName /reg:32

Output:

--- Accessing the Registry ---

Attempting to read with the default (64-bit) command...
ERROR: The system was unable to find the specified registry key or value.

Attempting to read with the /reg:32 switch...

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\7-Zip
    DisplayName    REG_SZ    7-Zip 19.00 (x86)

This clearly shows that the standard command fails, while the one with /reg:32 succeeds because it correctly looks in the Wow6432Node section.

How the /reg:32 Switch Works​

When you use /reg:32, you are sending a flag with your request to the Windows Registry API. This flag tells the operating system's registry redirector to "treat this request as if it came from a 32-bit application." In response, the redirector automatically maps your request for HKLM\SOFTWARE\... to the correct HKLM\SOFTWARE\Wow6432Node\... location.

Common Pitfalls and How to Solve Them​

Problem: The Script is Not Run as Administrator​

If you are trying to query or modify the HKEY_LOCAL_MACHINE (HKLM) hive, you will need elevated privileges.

Solution: The script must be run as an Administrator.

Problem: This Only Works on a 64-bit OS​

The /reg:32 switch and the SysWOW64 folder only exist on 64-bit versions of Windows. Running this command on a 32-bit OS will result in an error.

Solution: A robust script should first check if the OS is 64-bit.

IF NOT DEFINED ProgramFiles(x86) (
    ECHO This is a 32-bit OS. The /reg:32 switch is not applicable.
    GOTO :EOF
)
REM Proceed with the /reg:32 command...
danger

CRITICAL: Do NOT include Wow6432Node in your path

This is the most common mistake. When you use the /reg:32 switch, you must provide the standard, non-redirected path.The operating system handles the redirection for you.

WRONG: REG QUERY "HKLM\Software\Wow6432Node\MyApp" /reg:32 CORRECT: REG QUERY "HKLM\Software\MyApp" /reg:32

Practical Example: Finding the Install Path of a 32-bit Application​

This script needs to find where a 32-bit application is installed. It does so by querying the 32-bit "Uninstall" registry key for the application's InstallLocation.

@ECHO OFF
SETLOCAL
SET "InstallPath="

ECHO --- Finding the installation path for My 32-bit App ---
ECHO.

REM The standard path to the uninstall key.
SET "UninstallKey=HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\My32bitApp"

REM Use FOR /F to parse the output of the REG command with the /reg:32 switch.
FOR /F "tokens=2*" %%A IN (
    'REG QUERY "%UninstallKey%" /v InstallLocation /reg:32 2^>NUL'
) DO (
    SET "InstallPath=%%B"
)

IF DEFINED InstallPath (
    ECHO [SUCCESS] Application is installed at:
    ECHO "%InstallPath%"
) ELSE (
    ECHO [FAILURE] Could not find the application's installation path.
)
ENDLOCAL

Conclusion​

The /reg:32 switch for the REG.EXE command is the essential tool for correctly interacting with the 32-bit registry on a 64-bit version of Windows.

Key takeaways:

  • On a 64-bit OS, the registry is split into 64-bit and 32-bit (Wow6432Node) views.
  • Use the /reg:32 switch to tell the REG command to access the 32-bit view.
  • When using this switch, provide the standard registry path and let Windows handle the redirection.
  • You must run as an Administrator to access HKEY_LOCAL_MACHINE.
  • This technique is critical for finding and managing settings for legacy 32-bit applications from a modern 64-bit script.

Table of Contents