Hijacking the thread since I'm having this same problem. When I start the remote session screen is just blank (black) and only thing that fixes this is to set legacy capture mode on in host settings. After this all seems to work fine excep tfirefox window is blank (white) and I can't get it to work (unless i disable hardware acceleration which i wouldn't want to do). Setting alpha-blending capture does not affect this.. Both host and client are windows 10 latest version. Host is running on Nvidia gpu. Is there anything else that could solve the problem other than disabling H-A?