Cant getValueNames() from HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

Question

I want to read all Values out of the Registry that are in the

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

I am trying to do this with the following Code:

RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run", false);
        string[] values = key.GetValueNames();

But my values String is always empty. The interesting part about that is, if I change the Code to

 RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion", false);
        string[] values = key.GetValueNames();

I get the correct amount of ValueNames in CurrentVersion. Why does it not work in \Run? If I change from LocalMachine to CurrentUser the \Run path works too.

RegistryKey key = Registry.CurrentUser.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Run", false);
        string[] values = key.GetValueNames();

Can someone tell me why my first CodeExample does not work? Thanks!

Answer 1

You don't provide details on whether your C# application is 32-bit (x86) or 64-bit (x64). If the application is 32-bit running on 64-bit Windows, registry calls for HKLM\Software are redirected to HKLM\Software\Wow6432Node. Microsoft call this the Registry Redirector. Only certain keys are redirected, the details are in the linked article.

If your application is 64-bit, these registry calls are not redirected.

You can test this by manually adding a single REG_SZ entry of say "TestWOW" to HKLM\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run. Your 32-bit code should read this value (even though you actually asked for another registry key!).

If you can, re-compile your application as 64-bit. Now the same code will return the expected values from HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run.

Unfortunately, I'm not aware of a mechanism to force Windows to NOT re-direct your registry calls to the Wow64 node for 32-bit applications running on a 64-bit OS.