Question

string user = @"NT AUTHORITY\NETWORK SERVICE";
RegistryKey key = Registry.LocalMachine.OpenSubKey(@"SYSTEM\CurrentControlSet\services\eventlog");
RegistrySecurity regSec = new RegistrySecurity();
RegistryAccessRule rule = new RegistryAccessRule(
                user,
                RegistryRights.FullControl,
                InheritanceFlags.ContainerInherit | InheritanceFlags.ObjectInherit,
                PropagationFlags.InheritOnly,
                AccessControlType.Allow);
regSec.AddAccessRule(rule);

key.SetAccessControl(regSec);

I’m getting System.Unauthorizedaccessexception: “Cannot write to the registry key.” at key.SetAccessControl(regSec);

I’m running the app as admin.

Answer 1

I think Network Service account, by default, does not have write access to the registry.

See http://msdn.microsoft.com/en-us/library/ff647402.aspx#paght000015_registryaccess

The exception probably has nothing to with whether the app was run as admin.