As reported by Windows Latest, update KB4559309 is causing some PCs to slow down. Released to replace the old Edge browser with the new Chromium-based one, the KB4559309 update is hampering the performance of some laptops and desktops, especially during boot up.
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To make matters worse, the update is pushed out automatically, so you don’t have the option to opt-out as you would with a manual update. After your PC is forced to install the update, it could begin to slow down, as some users have recorded. “Since this update was installed I have had boot problems and can only boot in safe mode. Windows startup repair says it can’t fix the problem,” one user wrote on Microsoft’s community forums page (opens in new tab). Those concerns were echoed by several others in the 30-post thread. As with most Windows 10 errors, this issue only affects a portion of users, and from what we can tell, it’s a very small group. Chances are you won’t run into any performance problems after the update installs onto your machine. In fact, you’ll probably really enjoy the update, as the new Edge browser is a huge improvement over the previous one, and we even prefer it to Chrome.
What to do now
If you’re worried about how the KB4559309 update will impact your system, consider manually downloading the Chromium-based Edge browser. This will supposedly block the offending update from automatically installing onto your machine. If that ship has sailed, you can try reverting to an older version of Windows 10 by using the System Restore feature. Microsoft has this handy guide (opens in new tab) on how to roll back to an earlier version of Windows.