How to access the 64-bit registry from a 32-bit Powershell instance?

Question

If you launch a 32-bit instance of Powershell (%SystemRoot%\\syswow64\\WindowsPowerShell\\v1.0\\powershell.exe), then the registry provider only sees the limited 32-bit part

Answer 1

A slight variation of the answer from Milan is to host powershell using the C# program as per Bart De Smet's blog. Although that blog entry focusses on compiling against .NET 4.0, you can compile the same against .NET 3.5 as well. The result is a binary that is a PowerShell host that can access 64bit registry entires when invoked from a 32-bit process:

using System;
using System.Management.Automation.Runspaces;
using Microsoft.PowerShell;

namespace PSHost
{
    class Program
    {
        static void Main(string[] args)
        {

            var config = RunspaceConfiguration.Create();
            ConsoleShell.Start(
                config,
                "Windows PowerShell - Compiled for ANY CPU",
                "",
                args
            );

        }
    }
}