WiX 4 execute process system32\pnputil.exe from custom action

[vincentr]

I'm migrating my WiX3 installer to 4. We have C# custom actions where we execute pnputil.exe to install drivers. This works fine under v3. For v4 the process. Start() fails when the executable is in system32. The installer Package includes Scope="perMachine" to run elevated. Here is the exception I'm getting;

Exception thrown by custom action: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.ComponentModel.Win32Exception: The system cannot find the file specified at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo) at System.Diagnostics.Process.Start() at wixca.CustomActions.execProcess(Session session, String exePath, String exeArgs, String workingDir) at wixca.CustomActions.PostInstallAction(Session session) --- End of inner exception stack trace --- at System.RuntimeMethodHandle.InvokeMethod(Object target, Object arguments, Signature sig, Boolean constructor) at System.Reflection.RuntimeMethodInfo.UnsafeInvokeInternal(Object obj, Object parameters, Object arguments) at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object parameters, CultureInfo culture) at WixToolset.Dtf.WindowsInstaller.CustomActionProxy.InvokeCustomAction(Int32 sessionHandle, String entryPoint, IntPtr remotingDelegatePtr) CustomAction PostInstallAction returned actual error code 1603 (note this may not be 100% accurate if translation happened inside sandbox)

Code (example shows hardcoded path but using env to get systemroot):

            using (Process proc = new Process())
            {
                proc.StartInfo.UseShellExecute = false;
                proc.StartInfo.FileName = "c:\\windows\\system32\\pnputil.exe";
                proc.StartInfo.CreateNoWindow = true;
                proc.StartInfo.Arguments = "/add-driver driver.inf /install";
                proc.StartInfo.WorkingDirectory = "c:\\windows\\system32;
                proc.StartInfo.RedirectStandardOutput = true;
                proc.StartInfo.RedirectStandardError = true;
                proc.EnableRaisingEvents = true;
                proc.OutputDataReceived += new DataReceivedEventHandler(outputDataReceived);
                proc.ErrorDataReceived += new DataReceivedEventHandler(errorDataReceived);

                proc.Start();
                proc.BeginOutputReadLine();
                proc.BeginErrorReadLine();
                proc.WaitForExit();
                exitCode = proc.ExitCode;
            }

[vincentr]

Found the issue. The Visual Studio project for the custom action didn't have x64. Adding x64 to the solution via Configuration Manager and then selecting x64 for the CA platform then built the dll as 64 bit.

This also resolved registry access in HKLM to not be in WOW6432Node.