The recent update KB4516421 for Windows 10 Version 1903 has already resulted in many issues acknowledge by Microsoft. And now we can add two more to the list.

One more high CPU usage issue has been detected and acknowledged by Microsoft on its official 1903 issue tracker page.

IME may become unresponsive or have High CPU usage

Some Input Method Editor (IME) may become unresponsive or may have high CPU usage. Affected IMEs include Chinese Simplified (ChsIME.EXE) and Chinese Traditional (ChtIME.EXE) with Changjie/Quick keyboard.
Affected platforms:
  • Client: Windows 10, version 1903; Windows 10, version 1809; Windows 10 Enterprise LTSC 2019; Windows 10, version 1803; Windows 10, version 1709; Windows 10, version 1703; Windows 10 Enterprise LTSC 2016; Windows 10, version 1607
  • Server: Windows Server, version 1903; Windows Server, version 1809; Windows Server 2019; Windows Server, version 1803; Windows Server, version 1709 ; Windows Server 2016
Workaround: To mitigate the issue, perform the following steps:
  1. Select the Start button and type Services.

  2. Locate Touch Keyboard and Handwriting Panel Service and double click on it or

    long press

    and select Properties.

  3. Locate Startup type: and change it to Manual

  4. Select Ok

  5. The TabletInputService service is now in the default configuration and IME should work as expected.

Another issue with Intel and Broadcom Wi-Fi adapters have been acknowledged by Microsoft.

Safeguard on certain devices with some Intel and Broadcom Wi-Fi adapters

Microsoft and NEC have found incompatibility issues with Intel Centrino 6205/6235 and Broadcom 802.11ac Wi-Fi cards when running Windows 10, version 1903 on specific models of NEC devices. If these devices are updated to Windows 10, version 1903, they will no longer be able to use any Wi-Fi connections. The Wi-Fi driver may have a yellow exclamation point in device manager. The task tray icon for networking may show the icon for no internet and Network & Internet settings may not show any Wi-Fi networks.
To safeguard your update experience, we have applied a compatibility hold on the affected devices from being offered Windows 10, version 1903.
Affected platforms:
  • Client: Windows 10, version 1903
Workaround: If you are using an affected device and you have already installed Windows 10, version 1903, you can mitigate the issue disabling then re-enabling the Wi-Fi adapter in Device Manager. You should now be able to use Wi-Fi until your next reboot.
While Microsoft has provided workarounds for both these issues, it is still a temporary solution and Microsoft will fix these issues with a future update.