Same here
I have a setup where my iMac is connected via a LAN to the internet and is sharing the internet connection with devices that connect to my computer with a wifi connection. I have a macbook that normally connects fine with my iMac. But since recently (today 12 Sept) it has stopped working. My Macbook only sometimes sees my iMac but when I try to connect to it, I get a connection time out. Even when the macbook is sitting on the same desk just besides each other they can't connect. My iMac has had more success connecting to the macbook but that too doesn't really work. I can't really browse through the macbook it just shows up as an afp connection. Anybody has any suggestions or the same problem. The only thing I could think of is the front row, quicktime, iTunes up date that my desktop has done but not my laptop.