I have seen anti-virus utilities cause problems with Windows Update. And one of the problems was during a reboot to install the updates, the utility was active scanning and would not allow the Updates to be installed. So if you have an anti-virus, just turning off "Real Time Protection" may not be enough.
I use MSE and it has never caused that problem, but during testing another one did. It is hard to say which ones may or may not since they are updated and problems repaired.
You do shut your system all the way down occasionally?
If nothing else helps, you might use the site linked below. But one of the commands in the "do it myself" section does not run on my system. May be a typo, but before you do the fixit, or yourself, open an administrative command prompt and type: netsh winsock reset
Give it some time to see if it helps, then continue with the process if you want. How do I reset Windows Update components?