After installing the following updates, lots of users start complaining that Cortana (SearchUI.exe) showing high CPU usage even when the machine is idle. While for some users Cortana search stopped working.

August 30, 2019 — KB4512941 (OS Build 18362.329)August 30, 2019 — KB4511555 Cumulative Update for .NET Framework 3.5, 4.8 for Windows 10, version 1903

Fortunately, Reddit users in this thread explained very well about what causing the issue and how to fix it.

Fix – Windows 10 1903 Update (18362.329) Causes High CPU Usage (SearchUI.exe) & Search Not Working

Solution One All you have to do is to either set Value data for BingSearchEnabled to 1 or delete the key. After that reboot your computer and issues will be fixed. But after doing this, all the local search queries will be sent to Bing again. Now it’s up to you whether you want to go with this method or not. Solution Two There’s an alternate method which is shared by another Reddit user and its very effective. He created a batch script that easily removes the cache folder and replaces it with the one which is ripped from clean Windows 10 build 18362.295 You can download the batch script from here: Cortana Batch Script. Download the file, extract the folder using archiving tool and run “Fix Cortana Cache” batch script with administrator rights. Are you facing a Cortana CPU High usage issue? Which solution do you find handy for your computer? We would like to hear your opinion in the comments. Via – Deskmodder

Fix   High CPU Usage in Windows 10 1903 Update  18362 329  - 94