diff --git a/src/openrct2-ui/title/TitleSequencePlayer.cpp b/src/openrct2-ui/title/TitleSequencePlayer.cpp
index b536e37740..7702d2c98c 100644
--- a/src/openrct2-ui/title/TitleSequencePlayer.cpp
+++ b/src/openrct2-ui/title/TitleSequencePlayer.cpp
@@ -311,6 +311,9 @@ namespace OpenRCT2::Title
                 }
                 else
                 {
+                    // Inhibit viewport rendering while we're loading
+                    WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, true);
+
                     ReportProgress(0);
                     auto parkImporter = ParkImporter::Create(path);
 
@@ -338,6 +341,9 @@ namespace OpenRCT2::Title
                 GetContext()->CloseProgress();
             }
 
+            // Reset viewport rendering inhibition
+            WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, false);
+
             gLoadKeepWindowsOpen = false;
             return success;
         }
@@ -360,6 +366,9 @@ namespace OpenRCT2::Title
                 }
                 else
                 {
+                    // Inhibit viewport rendering while we're loading
+                    WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, true);
+
                     ReportProgress(0);
                     bool isScenario = ParkImporter::ExtensionIsScenario(hintPath);
                     auto parkImporter = ParkImporter::Create(hintPath);
@@ -387,6 +396,10 @@ namespace OpenRCT2::Title
                 Console::Error::WriteLine("Unable to load park: %s", hintPath.c_str());
                 GetContext()->CloseProgress();
             }
+
+            // Reset viewport rendering inhibition
+            WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, false);
+
             gLoadKeepWindowsOpen = false;
             return success;
         }
diff --git a/src/openrct2-ui/windows/Main.cpp b/src/openrct2-ui/windows/Main.cpp
index d452b384de..604bd9bab1 100644
--- a/src/openrct2-ui/windows/Main.cpp
+++ b/src/openrct2-ui/windows/Main.cpp
@@ -48,10 +48,6 @@ static Widget _mainWidgets[] = {
 
         void OnDraw(DrawPixelInfo& dpi) override
         {
-            // Skip viewport render during preloader
-            if (GetContext()->GetActiveScene() == GetContext()->GetPreloaderScene())
-                return;
-
             ViewportRender(dpi, viewport, { { dpi.x, dpi.y }, { dpi.x + dpi.width, dpi.y + dpi.height } });
         }
 
diff --git a/src/openrct2/Context.cpp b/src/openrct2/Context.cpp
index 32acf5e055..e23396795f 100644
--- a/src/openrct2/Context.cpp
+++ b/src/openrct2/Context.cpp
@@ -671,7 +671,7 @@ namespace OpenRCT2
             if (!gOpenRCT2Headless && forceDraw)
             {
                 _uiContext->ProcessMessages();
-                WindowUpdateAll();
+                WindowInvalidateByClass(WindowClass::ProgressWindow);
                 Draw();
             }
         }
@@ -766,6 +766,9 @@ namespace OpenRCT2
                     parkImporter = ParkImporter::CreateS6(*_objectRepository);
                 }
 
+                // Inhibit viewport rendering while we're loading
+                WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, true);
+
                 OpenProgress(asScenario ? STR_LOADING_SCENARIO : STR_LOADING_SAVED_GAME);
                 SetProgress(0, 100, STR_STRING_M_PERCENT, true);
 
@@ -785,6 +788,9 @@ namespace OpenRCT2
                 parkImporter->Import(gameState);
                 SetProgress(100, 100, STR_STRING_M_PERCENT, true);
 
+                // Reset viewport rendering inhibition
+                WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, false);
+
                 gScenarioSavePath = path;
                 gCurrentLoadedPath = path;
                 gFirstTimeSaving = true;
@@ -935,6 +941,7 @@ namespace OpenRCT2
             }
 
             CloseProgress();
+            WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, false);
             return false;
         }
 
diff --git a/src/openrct2/interface/Viewport.cpp b/src/openrct2/interface/Viewport.cpp
index c5bce15049..e8c293fdc5 100644
--- a/src/openrct2/interface/Viewport.cpp
+++ b/src/openrct2/interface/Viewport.cpp
@@ -927,6 +927,9 @@ void ViewportRotateAll(int32_t direction)
  */
 void ViewportRender(DrawPixelInfo& dpi, const Viewport* viewport, const ScreenRect& screenRect)
 {
+    if (viewport->flags & VIEWPORT_FLAG_RENDERING_INHIBITED)
+        return;
+
     auto [topLeft, bottomRight] = screenRect;
 
     if (bottomRight.x <= viewport->pos.x)
@@ -1018,6 +1021,9 @@ static void ViewportPaint(const Viewport* viewport, DrawPixelInfo& dpi, const Sc
     PROFILED_FUNCTION();
 
     const uint32_t viewFlags = viewport->flags;
+    if (viewFlags & VIEWPORT_FLAG_RENDERING_INHIBITED)
+        return;
+
     uint32_t width = screenRect.GetWidth();
     uint32_t height = screenRect.GetHeight();
     const uint32_t bitmask = viewport->zoom >= ZoomLevel{ 0 } ? 0xFFFFFFFF & (viewport->zoom.ApplyTo(0xFFFFFFFF)) : 0xFFFFFFFF;
diff --git a/src/openrct2/interface/Viewport.h b/src/openrct2/interface/Viewport.h
index e6994bb5d2..530c3ba4cf 100644
--- a/src/openrct2/interface/Viewport.h
+++ b/src/openrct2/interface/Viewport.h
@@ -66,6 +66,7 @@ enum : uint32_t
     VIEWPORT_FLAG_INVISIBLE_SUPPORTS = (1u << 29),
 
     VIEWPORT_FLAG_INDEPEDENT_ROTATION = (1u << 30),
+    VIEWPORT_FLAG_RENDERING_INHIBITED = (1u << 31),
 };
 
 enum class VisibilityKind
diff --git a/src/openrct2/interface/Window.cpp b/src/openrct2/interface/Window.cpp
index 19f9e0bb48..a942583e01 100644
--- a/src/openrct2/interface/Window.cpp
+++ b/src/openrct2/interface/Window.cpp
@@ -101,6 +101,19 @@ void WindowVisitEach(std::function<void(WindowBase*)> func)
     }
 }
 
+void WindowSetFlagForAllViewports(uint32_t viewportFlag, bool enabled)
+{
+    WindowVisitEach([&](WindowBase* w) {
+        if (w->viewport != nullptr)
+        {
+            if (enabled)
+                w->viewport->flags |= viewportFlag;
+            else
+                w->viewport->flags &= ~viewportFlag;
+        }
+    });
+}
+
 /**
  *
  *  rct2: 0x006ED7B0
diff --git a/src/openrct2/interface/Window.h b/src/openrct2/interface/Window.h
index a017c71f3c..2d5cff3e5f 100644
--- a/src/openrct2/interface/Window.h
+++ b/src/openrct2/interface/Window.h
@@ -491,6 +491,8 @@ extern bool gDisableErrorWindowSound;
 std::list<std::shared_ptr<WindowBase>>::iterator WindowGetIterator(const WindowBase* w);
 void WindowVisitEach(std::function<void(WindowBase*)> func);
 
+void WindowSetFlagForAllViewports(uint32_t viewportFlag, bool enabled);
+
 void WindowDispatchUpdateAll();
 void WindowUpdateAllViewports();
 void WindowUpdateAll();
diff --git a/src/openrct2/scenes/preloader/PreloaderScene.cpp b/src/openrct2/scenes/preloader/PreloaderScene.cpp
index 346c52d06b..1dd085e9d1 100644
--- a/src/openrct2/scenes/preloader/PreloaderScene.cpp
+++ b/src/openrct2/scenes/preloader/PreloaderScene.cpp
@@ -41,6 +41,7 @@ void PreloaderScene::Load()
     gameStateInitAll(GetGameState(), DEFAULT_MAP_SIZE);
     ViewportInitAll();
     ContextOpenWindow(WindowClass::MainWindow);
+    WindowSetFlagForAllViewports(VIEWPORT_FLAG_RENDERING_INHIBITED, true);
     WindowResizeGui(ContextGetWidth(), ContextGetHeight());
 
     // Reset screen