KB4517389 (OS Build 18362.418) 09th Oct 2019: This caused exactly the same issues as KB4524147 issue: .Apart from the ongoing issue that recent updates prevented search facility so had to uninstall them, with this update not only did search not work but unable to open notification panel AND start button not only did not work but got a pop up saying Critical error or some such and advising signing in again would rectify the problem. Which it didn’t. Eventually had to uninstall. All OK again.
***Modified title from: KB4517389 (OS Build 18362.418) caused same issues as KB4524147 !***