I did a manual install of KB4534310 and could now start the game but have microstutter that I did not have before that make the game unplayable.
I hope they do find the problem in the anticheat software because I do belive some change made to it is causing this.
As a strong supporter of anticheat I hope it also works better than today, because this great game is unfortunatly riddled with cheaters.
I have this same problem. Apex updated for me today, and when I went to play, I got the same message saying my Windows 7 was out of date, and I needed to install KB4534310. I updated through Windows Update. I then had the micro-stutter problem you mentioned. It only stuttered when I move my mouse. But it's a very bad stutter, and makes the game unplayable. I also tried manually installing KB4534314. But the stutter is still there. Tried rebooting my PC and my router, nothing seemed to help.
I've been playing Apex since it was released. Now I can't play at all. Looks like they've basically given the finger to Windows 7 players. I've been meaning to update to Windows 10, but just haven't had a chance to yet. Looks like they are forcing me to now. Which really sucks, seeing as how I've sunk money and time into this game. Thanks for the middle finger EA!
Community Manager
