Why can I not delete a Registry key, even though it is present?

Question

I am trying to delete registry key and its subkeys. My method takes a registry key as a string argument, and then locates and deletes it.

I am testing it with this key:

HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\InstallShield_{694AFFC3-93D4-4049-AF26-78739488EB4D}

And this is the method I have written:

static void RemoveRegKey(string registryKey)
{
  // Split the string to get the hive, middle section, and subkey name
  string[] regKeyParts = registryKey.Split('\\');
  // Hive
  string hive = regKeyParts[0].ToUpper();
  // Name
  string name = regKeyParts[regKeyParts.Length - 1];
  // Middle bit
  string keyPath = "";
  for (int i = 1; i < regKeyParts.Length - 1; i++)
  {
    keyPath = keyPath + regKeyParts[i] + "\\"; 
  }

  // Create my registry key
  RegistryKey regkey = null;
  switch (hive)
  {
    case ("HKEY_LOCAL_MACHINE"):
      regkey = Registry.LocalMachine;
      break;
    case ("HKEY_CURRENT_CONFIG"):
      regkey = Registry.CurrentConfig;
      break;
    case ("HKEY_CURRENT_USER"):
      regkey = Registry.CurrentUser;
      break;
    case ("HKEY_USERS"):
      regkey = Registry.Users;
      break;
    case ("HKEY_CLASSES_ROOT"):
      regkey = Registry.ClassesRoot;       
      break;
   }

   // Open the registry key (everything up to the parent of the key I want to delete
   using (RegistryKey rk = regkey.OpenSubKey(keyPath, true))
   {
        Console.WriteLine(rk.ToString());
        // This bit added to verify the subkey is present - it will output to console if found
        string[] sk =  rk.GetSubKeyNames();
        foreach (string s in sk)
        {
            if (s == name) { Console.WriteLine(s); }
        }

        // If the subkey is present, delete it
        if (regkey.OpenSubKey(name) != null)
        {
            Console.WriteLine("Registry key found - deleting it");
            regkey.DeleteSubKeyTree(name);
        }
        else
        {
            Console.WriteLine("Could not find reg key");
        }
    }    
}

The key is definitely present, as this section:

string[] sk =  rk.GetSubKeyNames();
foreach (string s in sk)
{
   if (s == name) { Console.WriteLine(s); }
}

gives the expected output shown in green here:

However, regkey.OpenSubKey(name) evaluates to null, as the output after shows.

Could not find reg key.

I am running this as an elevated user, and the key is not protected.

Rhys Jones Rhys Jones · Accepted Answer · 2016-06-29T09:34:57

Is it a typo in the code? Should this;

if (regkey.OpenSubKey(name) != null)

be

if (rk.OpenSubKey(name) != null)

And update the Delete too.

Why can I not delete a Registry key, even though it is present?

2 Answers