Did you upgrade your Windows 10 PC to 1607 also known as the anniversary update, only to find that it won’t install updates from your WSUS server? If so join the club. After some research, it appears that Microsoft figured out the issue and put in in their September cumulative update KB3189866.
To get this update to my network computers I had 2 options. Since I couldn’t get the affected PC’s to retrieve updates from my WSUS server, I either had to install the update manually or have each PC download the patch from Microsoft’s update servers. I chose to manually install the patch since I could not afford the bandwidth required to have each machine downloading updates from the internet at once.
Once I manually installed the KB3189866 update, each computer was able to contact my WSUS server, download the remaining updates and install them.