I have had this same "receiving..." black screen for 2 weeks but now it seems i have managed to find a fix for myself. The video memory set to "default" didn´t fix it for me like it seemed to fix everyone elses. I think it´s not relevant at all in this case, although i still left it in "default". The thing that did was I changed my SixLauncher launch parameter from "-maxMem=2047" to "-maxMem=512"(i am also using CO beta) and now i have played almost 4 hours in a row w/o crashing, freezing or the black "Receiving..." screen appearing. Hope this helps you! :D