Registry OpenSubkey returns null, although it is there

I have read almost all the other questions to this topic, but they usually resolved by using the wrong architecture view in the registry.

I am trying to open a subkey in "...\Outlook\Addins". I have the subkey available for both architectures ( "HKLM\Software... " and "HKLM\Software\Wow3264Node..." ). But I know through testing, that the code is looking under "WOW6432Node".

So here is the code snippet.

var hklm = RegistryKey.OpenBaseKey RegistryHive.LocalMachine,RegistryView.Default);
var reg = hklm.OpenSubKey(@"Software\Microsoft\Office\Outlook\Addins\MyAddin", false);

I also tried

var hklm = RegistryKey.OpenBaseKey RegistryHive.LocalMachine,RegistryView.Registry32);
var hklm = RegistryKey.OpenBaseKey RegistryHive.LocalMachine,RegistryView.Registry64);

to debug it and looked for the subkeys, that are visible, which give me all other entries (even newly created ones), but not the one I am looking for.

I also checked Registry Permissions, which are the same as for the others I can see.

So why do I receive always null for "reg"?

Edit: Maybe I should add, that I am looking for that key from inside the addin. When trying it from a short test console application, I see the subkey when calling

reg.GetSubKeyNames();

Solution

As it seems, this is a security "feature". There is no way of accessing the registry branch of the addin, which is looking for it. The information, which I would like to have stored there, needed to be stored somewhere else.