Editing Local_Machine RegistryKeys Programmatically (C#)

Question

I'm trying to make a program that changes the registry key values on remote machines to block/allow users from personalizing their lock-screen images. It seems the key I need to create is at HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Personalizationwith a name of NoChangingLockScreen. I could easily do this with a .reg file and merge any changes into their registry (I planned on creating a windows service to monitor for changes in the file), although it seems I cannot even modify any keys inside the HKEY_LOCAL_MACHINE class. Please note:

• I am a domain admin across our network, and all remote computers have admin rights
• This issue does not just occur when modifying a remote PC's keys, but my own as well
• I've created the RegistryKey object as writable (See below code)
• It seems I cannot even use the OpenSubKey method, as reading the local_machine path just throws an object exception
• I've checked the permissions inside the Registry for that specific class and made sure my account had full control

• I have found very little documentation on other people having permissions issues

  RegistryKey myKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Policies\Microsoft\Windows", true);
  

Answer 1

Registry.ClassesRoot is for HKEY_CLASSES_ROOT. You need to use Registry.LocalMachine field like this:

using (var registryKey = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Policies\Microsoft\Windows", writable: true))
{
    ...
}

Also note, that this is for local registry access. If you wish to open remote registry, you need to use another method:

using (var remoteBaseKey = RegistryKey.OpenRemoteBaseKey(RegistryHive.LocalMachine, "RemoteMachineName"))
using (var registryKey = remoteBaseKey.OpenSubKey(@"SOFTWARE\Policies\Microsoft\Windows", writable: true))
{
    ...
}