What Changed in RC4 with the January 2026 Windows Update and Why it is Important

Microsoft

Mar 23, 2026

In case you haven’t heard, RC4 is not secure and has been deprecated. In this article, I will discuss what changed with the January 2026 Windows Update and why it is important to start auditing and r...

Published Mar 23, 2026

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JoeMic1

Copper Contributor

Apr 05, 2026

RC4DefaultDisablementPhase requires rebooting the Domain Controllers.. no idea if that is why is not working for you

GarFin

Copper Contributor

Apr 06, 2026

Yes, Domain controllers all get rebooted as part of their Monthly Cumulative update patching, so therefore rebooted post Jan patch as well as February patching (and now March also) :(

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What Changed in RC4 with the January 2026 Windows Update and Why it is Important