How Can a 32-bit Application Access the 64-bit Windows Registry?

Read 64-bit registry from 32-bit application

When a 32-bit application is running on a 64-bit Windows system, it can only access the registry key under HKEY_LOCAL_MACHINESoftwareWow6432Node. However, in some cases, access to the 64-bit registry is required.

Solution:

Using .NET Framework 4.x and above:

.NET Framework 4.x and later provides the RegistryView enumeration, allowing direct access to 64-bit and 32-bit registry keys. Here’s how to do it:

Access 64-bit registry:

<code class="language-csharp">using Microsoft.Win32;

RegistryKey localKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
// 对64位注册表执行操作</code>

Access 32-bit registry:

<code class="language-csharp">RegistryKey localKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32);
// 对32位注册表执行操作</code>

Alternative:

For situations where you need to access both 64-bit and 32-bit registry keys, you can use the following method:

<code class="language-csharp">// 获取64位和32位节点的所有注册表值
var mergedValues = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64).GetValues()
    .Concat(RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).GetValues());

// 获取64位和32位节点的所有注册表项
var mergedKeys = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64).GetSubKeyNames()
    .Concat(RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).GetSubKeyNames());</code>

Note:

• Reading the 64-bit registry is possible thanks to Windows' WOW64 subsystem (which emulates 32-bit operations on 64-bit systems).
• In Windows 7, there is a bug where the 32-bit code version always returns "Microsoft" for RegisteredOrganization regardless of the actual value.
• In 32-bit versions of Windows, the WOW6432Node subtree does not exist.

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