Just wanted to post on the error I had this morning. After the massive KB3194496 yesterday I got the yellow exclamation mark on my network card, no Internet, no connections to local newtork. To save your reading on - the fix was to do a Repair of AVAST AV from Programs and Features.

The network card had picked up the self configured IP address that it gets when it can't reach DHCP. All other systems on my home network working fine. Tried many things (disabled/enabled network card, re-install network card driver, reboot home router, untinstall network card and re-boot). I then installed a USB wireless network card I have and this also failed to connect to my wireless network (but worked fine on another PC that has not yet had the Anniversary update and KB3194496). At this point I realised that the netword card driver was not the issue. I started reading up on KB3194496 (which I could see is what had changed since the network/internet was last working) and could see that it is a massive udpate - and tries to address many, many issues.

Thanks to a thread on tomshardware Realtek Ethernet LAN Card Stopped Working after Upgrade to Windows 10 [Solved] - windows 10 - Windows 10 and seeing that another user had a similar issue with the Anniversary update itself I tried doing a repair of AVAST AV using Control Panel - Programs and Features - Right Click on Avast Internet Security - select Change, and then Repair - followed by a reboot. After the reboot network was working fine. I should note that the startup and full loading of all my task tray icons took much, much longer than usual (so be patient if you try this). Avast did not seem to start up so I tried starting it from the Start Menu and it started successfully, ran an initial startup scan and I have been running fine for the past couple of hours.

Hope this helps anyone with a similar issue.