Why is the Registry Key showing null in C# even if it is present in Registry Editor?

Question

Here is my C# code:

using (RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Multimedia\SystemProfile", true))
{
key.CreateSubKey("NetworkThrottlingIndex");
key.SetValue("NetworkThrottlingIndex", "0000000a", RegistryValueKind.DWord);
key.CreateSubKey("SystemResponsiveness");
key.SetValue("SystemResponsiveness", "00000000", RegistryValueKind.DWord);
key.CreateSubKey("NoLazyMode");
key.SetValue("NoLazyMode", "1");
}

So what is happening here is that I am getting an error

System.NullReferenceException  

on the line

key.CreateSubKey("NetworkThrottlingIndex");  

because the key is null.

I checked several times but this key is present in my registry editor.

Any idea about what is wrong here?

Answer 1

Are you running a 32-bit process? On my system the key exists in the 64-bit view of the registry.

Answer 2

I think that key is null for one of two reasons:

1. The key was not found so OpenSubKey() will return null
2. You don't have permissions to open that key in write mode

Answer 3

Try RegistryView.Registry64 like the test I had posted in this thread