An end-user experiencing a black screen followed by disconnection when connecting to a virtual desktop can be caused by several issues. A shortage of vRAM on the Horizon virtual machine can result in insufficient resources to render the display, causing a black screen (B). Incorrect firewall configuration can block necessary network traffic, preventing proper communication and resulting in a black screen (D). Lastly, an incorrect video driver version on the Horizon virtual machine can cause compatibility issues leading to display problems and disconnections (E).