September's Windows 10 'Patch Tuesday' updates fix high CPU usage bug

Microsoft Surface Book 2
Microsoft Surface Book 2 (Image credit: Windows Central)

What you need to know

  • Microsoft's September "Patch Tuesday" updates are now available.
  • These updates focus on bug fixes and improvements for several Windows 10 releases.
  • Notably, the update for Windows 10 May 2019 Update PCs fixes the high CPU usage bug that sprung up this month.
  • The updates are available now via Windows Update.

Microsoft released a new batch of "Patch Tuesday" updates for Windows 10 PCs today. As with previous updates of this nature, these don't include any new features to check out. Rather, these updates focus on bug fixes and security updates across several Windows 10 releases.

For those running the Windows 10 May 2019 Update, you'll see KB4515384 (opens in new tab) (build 18362.356). Notably, this update includes a fix for an issue that causes high CPU usage from SearchUI.exe for some users. Here's a full look at what's included:

  • Provides protections against a new subclass of speculative execution side-channel vulnerabilities, known as Microarchitectural Data Sampling, for 32-Bit (x86) versions of Windows (CVE-2019-11091, CVE-2018-12126, CVE-2018-12127, CVE-2018-12130). Use the registry settings as described in the Windows Client and Windows Server articles. (These registry settings are enabled by default for Windows Client OS editions and Windows Server OS editions.)
  • 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.
  • Security updates to Microsoft Edge, Internet Explorer, Microsoft Scripting Engine, Windows App Platform and Frameworks, Windows Input and Composition, Windows Media, Windows Fundamentals, Windows Authentication, Windows Cryptography, Windows Datacenter Networking, Windows Storage and Filesystems, Windows Wireless Networking, the Microsoft JET Database Engine, Windows Kernel, Windows Virtualization, and Windows Server.

Anyone running the October 2018 Update will see a similar set of fixes with KB4512578 (opens in new tab) (build 17763.737). Here's what's new:

  • Provides protections against a new subclass of speculative execution side-channel vulnerabilities, known as Microarchitectural Data Sampling, for 32-Bit (x86) versions of Windows (CVE-2019-11091, CVE-2018-12126, CVE-2018-12127, CVE-2018-12130). Use the registry settings as described in the Windows Client and Windows Server articles. (These registry settings are enabled by default for Windows Client OS editions and Windows Server OS editions.)
  • Security updates to Microsoft Edge, Internet Explorer, Microsoft Scripting Engine, Windows App Platform and Frameworks, Windows Input and Composition, Windows Fundamentals, Windows Authentication, Windows Cryptography, the Microsoft JET Database Engine, Windows Kernel, Windows Virtualization, and Windows Server.

The list of fixes for Windows 10 versions 1803 and earlier are largely the same as those provided for the October 2018 Update. For the full release notes, you can check out Microsoft's support site (opens in new tab) for more. Otherwise, hit up Windows Update to download this month's "Patch Tuesday" updates for your PC.

Dan Thorp-Lancaster is the former Editor-in-Chief of Windows Central. He began working with Windows Central, Android Central, and iMore as a news writer in 2014 and is obsessed with tech of all sorts. You can follow Dan on Twitter @DthorpL and Instagram @heyitsdtl

6 Comments
  • Great fix...not. The "fix" just caused search to stop working entirely.
  • What do you mean by "Search"? Do you mean from the Start menu, from Explorer, indexing, something else? All of these still work fine for me (but I realize that doesn't mean it's also working for you).
  • Ah, I see WC posted a newer article where a lot of people are reporting search from the Start menu to have problems following the update, along with steps to fix (just uninstall the update from Update History). It works fine on the 3 computers I've updated so far, but apparently not so for many others.
  • Do I even dare, does it break more than it fixes??? Probably!!! Seemingly becoming a weekly occurrence now where I'm reading warning headlines stating the risks of applying an update, what a joke Microsoft and its precious Windows 10 has become.
  • I don't think you care. Probably even typed from a Windows 10 PC. People's obsessions over things they hate is quite alarming and funny at the same time.
  • One thing that really gets my goat is how updates like this mess up a number of my default settings.. >-(
    Where do I begin?
    Taskbar reverted to default state (all icons and shortcuts removed)
    All Quick access shortcuts GONE.
    Software / application specific settings have been lost (e.g. AutoDesk) which makes the software revert to it's default 'straight out of the box' state. All customizations have been removed and need to be re-installed.
    I can go on and on but my question is always WHY???? Why must it tamper with these things, it is SO counter productive! If Microsoft can't release a half decent update then please don't release it at all! As much as I hate the existing issues, I would much rather wait until an update is thoroughly tested before releasing it to the public and cause such a mess.