PC: Dell Venue 8 Pro with Windows 8.1
Last night I got a number of updates (I think it was 22 Important and 1 Optional). After they installed, the tablet's wifi stopped working. I can use System Restore to go back to before the updates and it is fine again, but then the updates break the wifi when they install.
Specifically, the wifi adapter itself cannot be enabled from "network adapters" in the network/sharing center. Clicking "Enable this network connection" shows the "enabling..." dialog for a few seconds, but the adapter remains disabled. However, under Device Manager the device is listed as OK and "working properly" in the status. No new driver was installed for the device during the updates, so there is no driver to roll back to.
Some fellow nerd has discovered it was two specific patches that cause the problem and wrote about it here. http://aurir.wordpress.com/2013/12/09/having-wifi-issues-with-dell-venue-pro-8-uninstall-microsoft-patch-kb2887595/
I've chatted with Microsoft Answer Techs online via the Microsoft Store website, and have opened case number 1226838593 for this issue. I've been told it is being escalated for a fix to the patch.