Running Powershell from C# gives error: `running scripts is disabled on this system`

Try running your Set-ExecutionPolicy -Scope CurrentUser step within the runspace, like this.

First, with my ExecutionPolicy for this user to Restricted, and I see the following error when i run this code:

RunspaceConfiguration runspaceConfiguration = RunspaceConfiguration.Create();

            using (Runspace runspace = RunspaceFactory.CreateRunspace(runspaceConfiguration))
            {
                runspace.Open();
                RunspaceInvoke scriptInvoker = new RunspaceInvoke(runspace);
                //scriptInvoker.Invoke("Set-ExecutionPolicy Unrestricted -Scope CurrentUser ");
                Pipeline pipeline = runspace.CreatePipeline();
                Command scriptCommand = new Command("C:\\temp\\test.ps1");
                Collection<CommandParameter> commandParameters = new Collection<CommandParameter>();

                pipeline.Commands.Add(scriptCommand);
                Collection<PSObject> psObjects;
                psObjects = pipeline.Invoke();
            }


 RunspaceInvoke scriptInvoker = new RunspaceInvoke(runspace);
 scriptInvoker.Invoke("Set-ExecutionPolicy -Scope CurrentUser -ExecutionPolicy Unrestricted");

Gives me

System.Management.Automation.PSSecurityException: 'File C:\temp\test.ps1 cannot be loaded because running scripts is disabled on this system. For more information, see about_Execution_Policies at https:/go.microsoft.com/fwlink/?LinkID=135170.'

Next, I rerun it, uncommenting this line:

scriptInvoker.Invoke("Set-ExecutionPolicy Unrestricted -Scope CurrentUser ");

And, no errors! However, this will change the users ExecutionPolicy, which I think is bad behavior, so I'm going to instead wrap my function with this and set the Users ExecutionPolicy back the way I found it.

using (Runspace runspace = RunspaceFactory.CreateRunspace(runspaceConfiguration))
            {
                runspace.Open();
                RunspaceInvoke scriptInvoker = new RunspaceInvoke(runspace);
                scriptInvoker.Invoke("$ExecutionPolicy = Get-ExecutionPolicy -Scope CurrentUser");
                scriptInvoker.Invoke("Set-ExecutionPolicy Unrestricted -Scope CurrentUser ");
                Pipeline pipeline = runspace.CreatePipeline();
                Command scriptCommand = new Command("C:\\temp\\test.ps1");
                Collection<CommandParameter> commandParameters = new Collection<CommandParameter>();

                pipeline.Commands.Add(scriptCommand);
                Collection<PSObject> psObjects;
                psObjects = pipeline.Invoke();
                scriptInvoker.Invoke("Set-ExecutionPolicy -Scope CurrentUser $ExecutionPolicy -Force");
            }

Now our function works and we don't tamper with the user's system settings.