diff --git a/src/d3d9/d3d9_device.cpp b/src/d3d9/d3d9_device.cpp index e3298247..5fa98f80 100644 --- a/src/d3d9/d3d9_device.cpp +++ b/src/d3d9/d3d9_device.cpp @@ -3436,6 +3436,10 @@ namespace dxvk { if (ppSwapChain == nullptr || pPresentationParameters == nullptr) return D3DERR_INVALIDCALL; + // Additional fullscreen swapchains are forbidden. + if (!pPresentationParameters->Windowed) + return D3DERR_INVALIDCALL; + m_implicitSwapchain->Invalidate(pPresentationParameters->hDeviceWindow); try {