Running a base version of Cinema 4D R19 (e.g., R19.000) on Windows 11 is a recipe for disaster. Early R19 builds had no knowledge of Windows 11’s security protocols, DPI scaling quirks, or graphics driver models (WDDM 3.0).

The critical updates for R19 are:

Without these updates, you risk:

Do not skip to R19.108 directly.

Windows 11 release: October 2021
Cinema 4D R19 support status by Maxon:

R19 relies heavily on OpenGL for its viewport rendering. Windows 11 and modern GPU drivers (NVIDIA/AMD) prioritize DirectX 12.