Retpoline Goes Default in Windows 10 Cumulative Update

Microsoft released a cumulative update for Windows 10 version 1809, the so-called Windows 10 October 2018 Update, to offer a wide range of improvements.

The headline change in cumulative update KB4482887 is the enabling of Retpoline "on certain devices." Retpoline is a more nuanced Spectre Variant 2 mitigation that is supposed to improve performance over the existing mitigations (well, eventually) that have a negative impact on performance.

Microsoft said in a blog post that Retpoline is currently disabled on "production Windows 10 client devices." The company plans to enable the feature via cloud configuration "over the coming months."

Aside from Retpoline, this cumulative update addresses many issues that lingered in the Windows 10 October 2018 Update after its wide release in January. (Hence the "so-called" caveat above.)

There are two known issues: authentication issues in Internet Explorer 11 for Windows Server users who are on the same account at the same time, and errors installing "certain types of MSI and MSP files."

The first issue is avoided by using separate user accounts and disabling "multiple RDP sessions for a single user account for a specific Windows Server." Microsoft said it plans to fix the issue later.

The advised solution to the second problem? "Ignore the error." Easy-peasy; we suspect that's what the majority of Windows users do anyway. Microsoft is also working to solve the issue in a later release.

KB4482887 is available now via Windows Update. If you prefer to install it manually, Microsoft said it "strongly recommends you install the latest servicing stack update (SSU)" before doing so.

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