The updates include vital improvements to security and reliability, addressing concerns raised over the past month. Unfortunately, they can also cause problems of their own.
According to users on Reddit, KB4103721 is bricking some user's PCs. The patch is the first for the Windows 10 April 2018 update, which had issues with microphones, driver compatibility, Chrome, and more.
“The update is bricking my computer,” said Reddit user Khaelis. “After the update (KB4103721) download and installs, after restarting my computer will hang on a black screen and do nothing. The only way to fix it is to restore my PC to a previous restore point, where the PC will boot up normally again. Automatic Updates then installed the update again and the issue returned. After a restore point, my PC booted again. Please fix this update so I can use my PC.”
Windows 10 Cumulative Update KB4103721 Changelog
The issue doesn't seem to affect all users, but a number have reported the same experience. Thankfully, restoring the PC to a previous Windows version fixes the issue, but it may be worth sitting this one out until we hear back from Microsoft.
If you can get it to work, KB4103721 fixes a number of bugs and security issues. Here's the changelog:
- “Addresses an issue with the April 2018 Windows Servicing update that causes App-V Scripts (User Scripts) to stop working.
Addresses an issue that may cause some devices to stop responding or working when using applications, such as Cortana or Chrome, after installing the Windows 10 April 2018 Update.
- Addresses an issue that prevents certain VPN apps from working on builds of Windows 10, version 1803. These apps were developed using an SDK version that precedes Windows 10, version 1803, and use the public RasSetEntryProperties API.
- Addresses additional issues with updated time zone information.
- Addresses an issue that may cause an error when connecting to a Remote Desktop server. For more information, see CredSSP updates for CVE-2018-0886.
- Security updates to Windows Server, Microsoft Edge, Internet Explorer, Microsoft scripting engine, Windows app platform and frameworks, Windows kernel, Microsoft Graphics Component, Windows storage and filesystems, HTML help, and Windows Hyper-V.”
KB4103727 for 1709 fixes issues with Internet Explorer, AMD and USB ports, various security problems, and more. KB4103723 is much the same, though it also adds protection against Spectre variant 2 and CPU spikes.
There are also updates for 1607, 1511, and RTM, so be sure to check for any known issues before installing. You can find more information about KB4103721 troubleshooting on Microsoft's community forums.