AutoUpdate.cs

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        private static void InstallUpdateSyncWithInfo()
        {
            try
            {
                if (ApplicationDeployment.IsNetworkDeployed)
                {
                    var ad = ApplicationDeployment.CurrentDeployment;
                    UpdateCheckInfo info = null;
                    try
                    {
                        info = ad.CheckForDetailedUpdate();
                    }
                    catch (DeploymentDownloadException dde)
                    {
                        MessageBox.Show(
                            @"The new version of the application cannot be downloaded at this time. Please check your network connection, or try again later. Error: " +
                            dde.Message);
                    }
                    catch (InvalidDeploymentException ide)
                    {
                        MessageBox.Show(
                            @"Cannot check for a new version of the application. The ClickOnce deployment is corrupt. Please redeploy the application and try again. Error: " +
                            ide.Message);
                    }
                    catch (InvalidOperationException ioe)
                    {
                        MessageBox.Show(
                            @"This application cannot be updated. It is likely not a ClickOnce application. Error: " +
                            ioe.Message);
                    }

                    if (info.UpdateAvailable)
                    {
                        try
                        {
                            ad.Update();
                            Application.Restart();
                        }
                        catch (DeploymentDownloadException dde)
                        {
                            MessageBox.Show(
                                @"Cannot install the latest version of the application. Please check your network connection, or try again later. Error: " +
                                dde);
                        }
                    }
                    else
                    {
                        new MainWindow().Show();
                    }
                }
                else
                {
                    MessageBox.Show(@"Not network deployed");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message + @" " + ex.StackTrace);
            }
        }

OnStartup.cs

        /// <summary>
        /// 
        /// </summary>
        /// <param name="e"></param>
        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            InstallUpdateSyncWithInfo();
        }