ManyCam 2.6.1 struggles with high-definition (1080p or 4K) hardware inputs. Lower your physical webcam's default resolution to 720p or 480p within the Windows Camera app before launching ManyCam. Recommended Alternatives

ManyCam cannot access your camera hardware if your operating system blocks it at the privacy level. Open Settings (Win + I). Navigate to Privacy & Security > Camera . Toggle Camera access to On .