Microsoft has released the first CU (Cumulative Updates) for RTM version of Windows 10 Fall Creators Update v.1709, which the RTM version has the build number of 16299.15. The KB4043961 updates the build version of Windows 10 v.1709 to build 16299.19.
The Cumulative Update Build 16299.20 (KB4043961) is rolled out to Windows Insiders running Build 16299.15 on Release Preview and Slow rings (Windows Insiders on Fast ring are getting Windows 10 RS4 (Redstone 4) Build 17017 instead). This update only includes quality improvements and no new OS features. Key improvements include:
Addressed issue where, after removing apps, they’re reinstalled on every restart, logoff, and login.
Addressed issue where localization of the error output from a JET database is broken. Only English error strings are reported.
Security updates to Windows kernel-mode drivers, Microsoft Graphics Component, Internet Explorer, Windows kernel, Microsoft Windows Search Component, Windows TPM, Windows NTLM, Device Guard, Microsoft Scripting Engine, Windows Wireless Networking, Microsoft Windows DNS, Windows Server, Microsoft JET Database Engine, and the Windows SMB Server.
If for some reasons, you’re not offered the KB4043961 Cumulative Updates even though you’re an Windows Insider, or you installed Windows 10 Fall Creators Update via Windows 10 v.1709 Media Creation Tool and are not joining Windows Insider program, or have opted out of Windows Insider program, the following tutorial guides you on how to install the KB4043961 CU manually.