Microsoft yesterday shipped
Windows 10 KB4515384 with a number of security improvements
and fix for Cortana’s high CPU usage bug. While Microsoft has
managed to resolve the high CPU usage caused by Cortana, it
looks like the update breaks down Windows Search once again.

In the changelog of Windows 10 KB4515384 (Build 18362.356),
Microsoft noted that the
update has addressed an issue that may have caused high CPU
usage for Cortana process (SearchUI.exe) on some PCs.

According to our own findings, the bug was hitting PCs that
used customized Windows 10 privacy-focused registry keys to
disable Bing integration in Windows Search. On Windows
Dashboard, Microsoft has marked
both CPU and broken Search issue as ‘resolved’.

“Addresses an issue that causes high CPU usage from
SearchUI.exe for a small number of users. This issue only
occurs on devices that have disabled searching the web using
Windows Desktop Search,” the company said.

This patch was apparently supposed to resolve Search issues as
well but as it turns out, it didn’t and it also broke the Start
menu for some users.

A number of users on Reddit
and Windows 10 Feedback Hub are reporting a blank search page
or a search page with an infinite loading icon after applying
the update.

“KB4515384 should address an issue that causes high CPU usage
from SearchUI.exe for a small number of users. But this update
again introduces the same problem as the previous update. Part
of the problem is a high CPU usage (~30%) and a totally broken
search function. Currently, I see no other option than to
blacklist this update also to prevent update to reinstall it
again and again,” a user documented the problem on Feedback
Hub.

“Sigh, searching for anything on the Start Menu results in a
blank window again after installing this update,” a user noted
on Reddit.

Start menu and other issues

According to posts on Reddit
and Microsoft
answer forum, Windows 10 update breaks down Start menu with
a critical error:

“Your Start menu isn’t working. We’ll try to fix it the next
time you sign in,” a message titled ‘Critical error’ reads, and
it includes a link to sign out.

“I tried install KB4515384 on one of my workstation with no
luck. Menu start stopped working with critical error and sign
out demand. After uninstall latest CU problem with start menu
was solved but action center won’t open now. Reinstalling
update do nothing. Windows 10 especially 1903 is the most
bugged OS ever. I suggest stay at 18362.295 as long as possible
or until all flaws will be finally fixed,” a user noted.

Again, a small number of users are experiencing this problem.

A few users are also reporting problems with Action
Center and external USB
devices such as the keyboard.

At the time of writing this story, Microsoft is not aware of
any issues with the update.