Windows Server 2012 - Access to registry denied when running powershell scripts from C#

Question

I'm building a C# application that has to run some powershell scripts.

While the application works well on all my colleagues computers, I have issue having it to work properly on a Windows Server 2012 virtual machine.

Whenever I run a script through the application I'm getting the following error message:

Access to the registry key 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\PowerShell\1\ShellIds\Microsoft.PowerShell' is denied. To change the execution policy for the default (LocalMachine) scope, start Windows PowerShell with the "Run as administrator" option. To change the execution policy for the current user, run "Set-ExecutionPolicy -Scope CurrentUser".

I precise that I went through a LOT of topics and tried many things that did not solve my problem I tried:

set-executionpolicy unrestricted

set-executionpolicy unrestricted -Scope -CurrentUser

And of course I ran these commands on both x64 and x86 powershell instances (running the powershell application as administrator)

Now the strange part is that I have no trouble running the script through the powershell window directly, the error only occurs when running the script through the C# application.

Here's the code involved:

public static List<string> RunPowerShellScript(Sequence sq, Script script)
    {
        try
        {
            script.Results = new List<Result>();

            Runspace runspace = RunspaceFactory.CreateRunspace();
            runspace.Open();
            RunspaceInvoke runspaceInvoker = new RunspaceInvoke(runspace);
            //runspaceInvoker.Invoke("set-executionpolicy bypass");
            runspaceInvoker.Invoke("set-executionpolicy unrestricted");

            //Create a pipeline to send variables 
            Pipeline pipeline = runspace.CreatePipeline();

            //Create a command
            Command myCommand = new Command(Properties.Settings.Default.Scripts + "\\" + script.ScriptName + ".ps1", false);
            foreach (Parameter p in script.Parameters)
            {
                CommandParameter param = new CommandParameter(p.ParameterName, sq.GetUpdatedParameter(p));
                myCommand.Parameters.Add(param);
            }

            pipeline.Commands.Add(myCommand);

            //Return the output from the script
            Collection<PSObject> returnObjects = pipeline.Invoke();
            runspace.Close();

            List<string> output = new List<string>();
            foreach (PSObject po in returnObjects)
            {
                if (po != null)
                    output.Add(po.ToString());
            }

            return output;
        }
        catch(Exception e)
        {
            return new List<string> { e.Message, "1" };
        }
    }

This may have something to do with you not running the powershell script in the same instance your running your execution policy change, try powershell –ExecutionPolicy Bypass -File C:\Path\to\Script. You will want to run this as a shell command (CMD) rather than a powershell command and it will knock the powershell script open. — Harvey
I'm not sure what you're suggesting, should I change my c# code to run the script from cmd instead of using the RunspaceFactory ? Because, it does work from cmd indeed, but that's not new, it does work from the powershell windows as well, but not from the c# application — Marc
Use System.Diagnostics.Process.Start("CMD.exe", powershell -ExecutionPolicy Bypass -File C:\Path\to\Script);'That will open a cmd and run the Powershell script with execution policy bypassed — Harvey
I'm gonna have to try that, that's not really convenient with my code and the dynamic passing of parameters but I'll give a shot — Marc
Use Get-ExecutionPolicy -List in a Powershell window to verify that your domain for the Windows Server is not overriding your policy change with a group policy. If it is, then there really isn't much you can do to change it without asking your domain administrator to change the GP — Harvey

Prem Sagar Prem Sagar · Accepted Answer · 2021-01-27T12:17:42

To resolve this issue, Open powershell as an administrator and run the command again:

Set-ExecutionPolicy Unrestricted

Windows Server 2012 - Access to registry denied when running powershell scripts from C#

2 Answers