I am using Windows 10 Pro 32-bit, Firefox Version 62.0.3 Build ID 20181001155545 After Windows installed updates I can't watch videos on Netflix (all videos) only, YouTube work just fine. I searched for the Netflix error and found that it says it's typically related to the browser. Netflix Error M7121-1331 I knew nothing else with the computer changed except Windows Updates so I uninstalled that update KB4464218 and rebooted. Problem Solved! The problem is that this is an important Windows Update and it keeps getting reinstalled automatically, and then the problem comes back with Netflix, and I have to go in and uninstall it again. Thanks in advance for any advice.