Why can protected video fail when I use a virtual screen?

BetterDisplay virtual screens do not provide an HDCP-protected display connection. A video service that requires a protected playback path can therefore refuse playback when your desktop uses a virtual screen, even though ordinary apps and unprotected videos display correctly.

Mirroring the virtual screen to an HDCP-capable physical monitor does not give the virtual screen that capability. A higher virtual resolution, HDR mode or Pro license does not add it either.

To check the playback path, stop the virtual-screen presentation, disconnect the virtual screen in BetterDisplay, and play the video directly on the physical display using its ordinary macOS desktop. Check the service’s requirements for the browser, display, cable and adapters. For example, Netflix’s Mac playback requirements specify an HDCP 2.2 connection for external displays used for Ultra HD playback.

Playback requirements and fallback behavior belong to the service and player. A video that worked previously does not establish that the same virtual-display path will remain supported. Conversely, a black video area alone does not prove that HDCP is the cause: if direct physical-display playback also fails, continue with the service’s own troubleshooting.