diff --git a/Userland/Applets/Keymap/KeymapStatusWindow.cpp b/Userland/Applets/Keymap/KeymapStatusWindow.cpp
index ae4c1bd068..850198682b 100644
--- a/Userland/Applets/Keymap/KeymapStatusWindow.cpp
+++ b/Userland/Applets/Keymap/KeymapStatusWindow.cpp
@@ -6,9 +6,9 @@
  */
 
 #include "KeymapStatusWindow.h"
-#include <LibCore/Process.h>
 #include <LibGUI/ConnectionToWindowMangerServer.h>
 #include <LibGUI/Painter.h>
+#include <LibGUI/Process.h>
 #include <LibKeyboard/CharacterMap.h>
 
 void KeymapStatusWidget::mousedown_event(GUI::MouseEvent& event)
@@ -16,7 +16,7 @@ void KeymapStatusWidget::mousedown_event(GUI::MouseEvent& event)
     if (event.button() != GUI::MouseButton::Primary)
         return;
 
-    MUST(Core::Process::spawn("/bin/KeyboardSettings"));
+    GUI::Process::spawn_or_show_error(window(), "/bin/KeyboardSettings");
 }
 
 KeymapStatusWindow::KeymapStatusWindow()
diff --git a/Userland/Applications/Browser/BrowserWindow.cpp b/Userland/Applications/Browser/BrowserWindow.cpp
index fd81e4263c..8f66fef667 100644
--- a/Userland/Applications/Browser/BrowserWindow.cpp
+++ b/Userland/Applications/Browser/BrowserWindow.cpp
@@ -16,7 +16,6 @@
 #include "Tab.h"
 #include <Applications/Browser/BrowserWindowGML.h>
 #include <LibConfig/Client.h>
-#include <LibCore/Process.h>
 #include <LibCore/StandardPaths.h>
 #include <LibCore/Stream.h>
 #include <LibGUI/AboutDialog.h>
@@ -27,6 +26,7 @@
 #include <LibGUI/Menu.h>
 #include <LibGUI/Menubar.h>
 #include <LibGUI/MessageBox.h>
+#include <LibGUI/Process.h>
 #include <LibGUI/SeparatorWidget.h>
 #include <LibGUI/Statusbar.h>
 #include <LibGUI/TabWidget.h>
@@ -301,8 +301,8 @@ void BrowserWindow::build_menus()
 
     settings_menu.add_separator();
     auto open_settings_action = GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/settings.png").release_value_but_fixme_should_propagate_errors(),
-        [](auto&) {
-            MUST(Core::Process::spawn("/bin/BrowserSettings"));
+        [this](auto&) {
+            GUI::Process::spawn_or_show_error(this, "/bin/BrowserSettings");
         });
     settings_menu.add_action(move(open_settings_action));
 
diff --git a/Userland/Applications/Settings/main.cpp b/Userland/Applications/Settings/main.cpp
index 9d62b24a92..74368deef9 100644
--- a/Userland/Applications/Settings/main.cpp
+++ b/Userland/Applications/Settings/main.cpp
@@ -5,7 +5,6 @@
  */
 
 #include <AK/QuickSort.h>
-#include <LibCore/Process.h>
 #include <LibCore/System.h>
 #include <LibDesktop/AppFile.h>
 #include <LibGUI/Application.h>
@@ -14,6 +13,7 @@
 #include <LibGUI/IconView.h>
 #include <LibGUI/Menu.h>
 #include <LibGUI/Model.h>
+#include <LibGUI/Process.h>
 #include <LibGUI/Statusbar.h>
 #include <LibGUI/Window.h>
 #include <LibMain/Main.h>
@@ -104,7 +104,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
         auto launch_origin_rect = icon_view->to_widget_rect(icon_view->content_rect(index)).translated(icon_view->screen_relative_rect().location());
         setenv("__libgui_launch_origin_rect", String::formatted("{},{},{},{}", launch_origin_rect.x(), launch_origin_rect.y(), launch_origin_rect.width(), launch_origin_rect.height()).characters(), 1);
-        MUST(Core::Process::spawn(executable));
+        GUI::Process::spawn_or_show_error(window, executable);
     };
 
     auto statusbar = TRY(main_widget->try_add<GUI::Statusbar>());
diff --git a/Userland/Applications/Terminal/main.cpp b/Userland/Applications/Terminal/main.cpp
index 3ebdae7b11..8a20d59897 100644
--- a/Userland/Applications/Terminal/main.cpp
+++ b/Userland/Applications/Terminal/main.cpp
@@ -11,7 +11,6 @@
 #include <LibConfig/Listener.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/DirIterator.h>
-#include <LibCore/Process.h>
 #include <LibCore/System.h>
 #include <LibDesktop/Launcher.h>
 #include <LibGUI/Action.h>
@@ -27,6 +26,7 @@
 #include <LibGUI/Menu.h>
 #include <LibGUI/Menubar.h>
 #include <LibGUI/MessageBox.h>
+#include <LibGUI/Process.h>
 #include <LibGUI/TextBox.h>
 #include <LibGUI/Widget.h>
 #include <LibGUI/Window.h>
@@ -328,7 +328,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto open_settings_action = GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/settings.png").release_value_but_fixme_should_propagate_errors(),
         [&](auto&) {
-            MUST(Core::Process::spawn("/bin/TerminalSettings"));
+            GUI::Process::spawn_or_show_error(window, "/bin/TerminalSettings");
         });
 
     TRY(terminal->context_menu().try_add_separator());
@@ -336,7 +336,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     auto file_menu = TRY(window->try_add_menu("&File"));
     TRY(file_menu->try_add_action(GUI::Action::create("Open New &Terminal", { Mod_Ctrl | Mod_Shift, Key_N }, Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-terminal.png").release_value_but_fixme_should_propagate_errors(), [&](auto&) {
-        MUST(Core::Process::spawn("/bin/Terminal"));
+        GUI::Process::spawn_or_show_error(window, "/bin/Terminal");
     })));
 
     TRY(file_menu->try_add_action(open_settings_action));
diff --git a/Userland/Applications/Welcome/WelcomeWidget.cpp b/Userland/Applications/Welcome/WelcomeWidget.cpp
index 3ce0cacf6f..e580d0d717 100644
--- a/Userland/Applications/Welcome/WelcomeWidget.cpp
+++ b/Userland/Applications/Welcome/WelcomeWidget.cpp
@@ -9,12 +9,12 @@
 #include <Applications/Welcome/WelcomeWindowGML.h>
 #include <LibConfig/Client.h>
 #include <LibCore/File.h>
-#include <LibCore/Process.h>
 #include <LibGUI/Application.h>
 #include <LibGUI/Button.h>
 #include <LibGUI/CheckBox.h>
 #include <LibGUI/Label.h>
 #include <LibGUI/Painter.h>
+#include <LibGUI/Process.h>
 #include <LibGfx/Font/BitmapFont.h>
 #include <LibGfx/Palette.h>
 #include <LibMarkdown/Document.h>
@@ -53,8 +53,8 @@ WelcomeWidget::WelcomeWidget()
 
     m_help_button = *find_descendant_of_type_named<GUI::Button>("help_button");
     m_help_button->set_icon(Gfx::Bitmap::try_load_from_file("/res/icons/16x16/book-open.png").release_value_but_fixme_should_propagate_errors());
-    m_help_button->on_click = [](auto) {
-        MUST(Core::Process::spawn("/bin/Help"sv));
+    m_help_button->on_click = [&](auto) {
+        GUI::Process::spawn_or_show_error(window(), "/bin/Help"sv);
     };
 
     m_new_button = *find_descendant_of_type_named<GUI::Button>("new_button");
diff --git a/Userland/Services/Taskbar/ClockWidget.cpp b/Userland/Services/Taskbar/ClockWidget.cpp
index 0c5a0649f6..abbf982df9 100644
--- a/Userland/Services/Taskbar/ClockWidget.cpp
+++ b/Userland/Services/Taskbar/ClockWidget.cpp
@@ -6,8 +6,8 @@
 
 #include "ClockWidget.h"
 #include <LibConfig/Client.h>
-#include <LibCore/Process.h>
 #include <LibGUI/Painter.h>
+#include <LibGUI/Process.h>
 #include <LibGUI/SeparatorWidget.h>
 #include <LibGUI/Window.h>
 #include <LibGfx/Font/FontDatabase.h>
@@ -153,8 +153,8 @@ ClockWidget::ClockWidget()
     m_calendar_launcher->set_fixed_size(24, 24);
     m_calendar_launcher->set_icon(Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-calendar.png").release_value_but_fixme_should_propagate_errors());
     m_calendar_launcher->set_tooltip("Calendar");
-    m_calendar_launcher->on_click = [](auto) {
-        MUST(Core::Process::spawn("/bin/Calendar"));
+    m_calendar_launcher->on_click = [this](auto) {
+        GUI::Process::spawn_or_show_error(window(), "/bin/Calendar");
     };
 }
 
diff --git a/Userland/Services/Taskbar/main.cpp b/Userland/Services/Taskbar/main.cpp
index 852663946e..5778cd9042 100644
--- a/Userland/Services/Taskbar/main.cpp
+++ b/Userland/Services/Taskbar/main.cpp
@@ -11,7 +11,6 @@
 #include <LibConfig/Client.h>
 #include <LibCore/ConfigFile.h>
 #include <LibCore/EventLoop.h>
-#include <LibCore/Process.h>
 #include <LibCore/StandardPaths.h>
 #include <LibCore/System.h>
 #include <LibDesktop/AppFile.h>
@@ -21,6 +20,7 @@
 #include <LibGUI/ConnectionToWindowMangerServer.h>
 #include <LibGUI/ConnectionToWindowServer.h>
 #include <LibGUI/Menu.h>
+#include <LibGUI/Process.h>
 #include <LibGfx/SystemTheme.h>
 #include <LibMain/Main.h>
 #include <WindowServer/Window.h>
@@ -32,7 +32,15 @@
 #include <unistd.h>
 
 static ErrorOr<Vector<String>> discover_apps_and_categories();
-static ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu();
+struct WindowRefence {
+    GUI::Window* window { nullptr };
+    GUI::Window* get()
+    {
+        VERIFY(window);
+        return window;
+    }
+};
+static ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu(WindowRefence&);
 
 ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
@@ -53,10 +61,15 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
 
     TRY(Core::System::pledge("stdio recvfd sendfd proc exec rpath"));
 
-    auto menu = TRY(build_system_menu());
+    // FIXME: Have to awkwardly pass a reference to the window pointer to build_system_menu(), that will be resolved later.
+    // (It is always valid at use)
+    WindowRefence window_ref {};
+    auto menu = TRY(build_system_menu(window_ref));
     menu->realize_menu_if_needed();
 
     auto window = TRY(TaskbarWindow::try_create(move(menu)));
+    window_ref.window = window.ptr();
+
     window->show();
 
     window->make_window_manager(
@@ -103,13 +116,13 @@ ErrorOr<Vector<String>> discover_apps_and_categories()
     return sorted_app_categories;
 }
 
-ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu()
+ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu(WindowRefence& window_ref)
 {
     Vector<String> const sorted_app_categories = TRY(discover_apps_and_categories());
     auto system_menu = TRY(GUI::Menu::try_create("\xE2\x9A\xA1")); // HIGH VOLTAGE SIGN
 
-    system_menu->add_action(GUI::Action::create("&About SerenityOS", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/ladyball.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
-        MUST(Core::Process::spawn("/bin/About"sv));
+    system_menu->add_action(GUI::Action::create("&About SerenityOS", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/ladyball.png").release_value_but_fixme_should_propagate_errors(), [&](auto&) {
+        GUI::Process::spawn_or_show_error(window_ref.get(), "/bin/About"sv);
     }));
 
     system_menu->add_separator();
@@ -228,13 +241,13 @@ ErrorOr<NonnullRefPtr<GUI::Menu>> build_system_menu()
         }
     }
 
-    system_menu->add_action(GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-settings.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
-        MUST(Core::Process::spawn("/bin/Settings"sv));
+    system_menu->add_action(GUI::Action::create("&Settings", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-settings.png").release_value_but_fixme_should_propagate_errors(), [&](auto&) {
+        GUI::Process::spawn_or_show_error(window_ref.get(), "/bin/Settings"sv);
     }));
 
     system_menu->add_separator();
-    system_menu->add_action(GUI::Action::create("&Help", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-help.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
-        MUST(Core::Process::spawn("/bin/Help"sv));
+    system_menu->add_action(GUI::Action::create("&Help", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-help.png").release_value_but_fixme_should_propagate_errors(), [&](auto&) {
+        GUI::Process::spawn_or_show_error(window_ref.get(), "/bin/Help"sv);
     }));
     system_menu->add_action(GUI::Action::create("&Run...", Gfx::Bitmap::try_load_from_file("/res/icons/16x16/app-run.png").release_value_but_fixme_should_propagate_errors(), [](auto&) {
         posix_spawn_file_actions_t spawn_actions;