Long-time Windows 10 users certainly know that installing cumulative updates is often a risky bet, and this is mostly because of the issues these updates end up causing.
During the beginning of Windows 10, these cumulative updates just didn't install and frequently pushed devices into a continuous loop where they were offered the patch just for the installation to finish unexpectedly after which be provided the update once again.
While these issues have apparently been resolved and the updates now install correctly, nowadays there are occasional releases that cause other problems around the Windows 10 devices where they're installed.
This update comes with a welcome group of improvements, and it also resolves an issue breaking down Windows Sandbox, an issue that Microsoft acknowledged in May.
But simultaneously, it also causes high CPU usage around the devices where it's installed. Microsoft is yet to understand the issue, but a quick search on Google reveals there are plenty of users experiencing this behavior.
Initially, the easiest workaround would be to uninstall this cumulative update, but this obviously means you're going to miss all these latest improvements. There's another approach to fix our prime CPU usage, and I'm likely to detail it below.
The high CPU usage bug
First of all, let's see what's causing the high CPU usage.
After closer inspection, it appears as though to blame in this case is really a process called SearchUI.exe and which belongs to digital assistant Cortana. The operation is located at the following location:
The procedure ought to be there even if you disabled Cortana, albeit I haven't received confirmation that top CPU usage is experienced on these units.
Because of this high CPU usage, devices where the update is installed end up hitting other problems, such as not being able to launch the beginning menu, so instead they simply display a large white box.
How to fix the bug
Fixing the bug is dependant on editing a registry key, albeit as you'll figure out in a couple of seconds, this might 't be your favorite bag.
The registry key is called BingSearchEnabled, and it's responsible for allowing and blocking search queries that you do in your device from being delivered to Bing. In other words, if you would like your searches to be performed locally and no Bing search engine results to become shown on the desktop, you most likely disabled this selection which registry key should be disabled.
The odd thing is that you need to enable this registry key (and thus let the feature to allow searches to become delivered to Bing) to be able to fix the problem. Deleting BingSearchEnabled helps too because the default behavior will be restored.
The bottom line is found at the next address within the Registry Editor (Start menu > regedit.exe):
Once you reach this address, just double-click the aforementioned admission to change its value to 1 or delete it. Rebooting the unit should save your valuable settings and correct the high CPU usage, albeit remember that looking behavior is going to be restored to default as well.
We've reached out to Microsoft to inquire about more information about the bug and see if the company is already investigating it. The following batch of cumulative updates is expected in a few days once the software giant begins the rollout from the September 2019 Patch Tuesday fixes.