What's wrong with Registry.GetValue?

Question

I trying to get a registry value:

var value = Registry.GetValue(@\"HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Cryptography\", \"MachineGuid\", 0);

Answer 1

It probably has to do with UAC (User Account Control). The extra layer of protection for Windows Vista and Windows 7.

You'll need to request permissions to the registry.

EDIT: Your code right now:

var keys = Registry.LocalMachine.OpenSubKey("SOFTWARE")
    .OpenSubKey("Microsoft")
    .OpenSubKey("Cryptography", RegistryKeyPermissionCheck.ReadSubTree)
    .GetValueNames();

Only requests the permissions on the Cryptography subkey, maybe that causes the problem (at least I had that once), so the new code would then be:

var keys = Registry.LocalMachine.OpenSubKey("SOFTWARE", RegistryKeyPermissionCheck.ReadSubTree)
    .OpenSubKey("Microsoft", RegistryKeyPermissionCheck.ReadSubTree)
    .OpenSubKey("Cryptography", RegistryKeyPermissionCheck.ReadSubTree)
    .GetValueNames();

EDIT2:
I attached the debugger to it, on this code:

var key1 = Registry.LocalMachine.OpenSubKey("SOFTWARE", RegistryKeyPermissionCheck.ReadSubTree);
var key2 = key1.OpenSubKey("Microsoft", RegistryKeyPermissionCheck.ReadSubTree);
var key3 = key2.OpenSubKey("Cryptography", RegistryKeyPermissionCheck.ReadSubTree);
var key4 = key3.GetValueNames();

It turns out, you can read that specific value, at least that's my guess, because all data is correct, until I open key3, there the ValueCount is zero, instead of the expected 1.

I think it's a special value that's protected.