Microsoft releases emergency updates to fix Windows Server issues

Microsoft releases emergency updates to fix Windows Server issues By Sergiu Gatlan April 20, 2026 04:30 AM 0 Microsoft has released out-of-band (OOB) updates to fix issues affecting Windows Server systems after installing the April 2026 security updates. As Microsoft confirmed last week, some admins may experience failures when installing the KB5082063 security update on Windows Server 2025 devices. Additionally, this month's Patch Tuesday cumulative updates are causing some Windows servers with domain controller roles to enter a restart loop due to crashes of the Local Security Authority Subsystem Service (LSASS). Microsoft also warned that this issue may also occur when setting up new domain controllers (or even on existing ones) if the server processes authentication requests very early during startup. To address these two known issues, Microsoft has released emergency updates for the following affected Windows Server versions: Windows Server 2025: KB5091157 (OS Build 26100.32698) Windows Server, version 23H2: KB5091571 (OS Build 25398.2276) Windows Server 2022: KB5091575 (OS Build 20348.5024) Windows Server 2019: KB5091573 (OS Build 17763.8647) Windows Server 2016: KB5091572 (OS Build 14393.9062) Windows Server 2025 Datacenter: Azure Edition: Hotpatch KB5091470 (OS Build 26100.32704) Windows Server 2022 Datacenter: Azure Edition: Hotpatch KB5091576 (OS Build 20348.5029) "The Windows Server 2025 OOB update (KB5091157) addresses both the installation failure issue and the domain controller restart issue," Microsoft explained. "OOB updates released for other supported Windows Server versions address only the domain controller restart issue." On Wednesday, Microsoft also warned admins that some Windows Server 2025 devices will boot into BitLocker recovery and prompt users to enter a BitLocker key after installing the KB5082063 Windows security update. Additionally, last week, it finally addressed a bug that has been plaguing Windows servers since September 2024, causing devices running Windows Server 2019 and Windows Server 2022 to upgrade to Windows Server 2025 "unexpectedly." Since the start of the year, Microsoft has also released emergency updates to resolve a Bluetooth device visibility bug and patch security vulnerabilities in the Routing and Remote Access Service (RRAS) management tool that affect hotpatch-enabled Windows 11 Enterprise devices. Two other sets of out-of-band updates addressed broken sign-ins with Microsoft accounts and update installation issues affecting the March 2026 non-security preview update. 99% of What Mythos Found Is Still Unpatched. AI chained four zero-days into one exploit that bypassed both renderer and OS sandboxes. A wave of new exploits is coming. At the Autonomous Validation Summit (May 12 & 14), see how autonomous, context-rich validation finds what's exploitable, proves controls hold, and closes the remediation loop. Claim Your Spot Related Articles: Microsoft: Some Windows servers enter reboot loops after April patches Microsoft: April Windows Server 2025 update may fail to install New Windows 11 emergency update fixes preview update install issues New Windows 11 hotpatch fixes Bluetooth device visibility issue Recently leaked Windows zero-days now exploited in attacks