Microsoft has released out-of-band (OOB) updates today, April 19, 2026, to address issues introduced by the April 2026 Windows security update.
A limited number of Windows Server 2025 devices might experience failures installing the April 2026 security update (KB5082063). In addition, some versions of Windows Server may experience domain controllers restarting repeatedly after installing the April 2026 security update.
To address these issues, Microsoft has released OOB updates for the Windows Server versions listed below. Note: The Windows Server 2025 OOB update (KB5091157) addresses both the installation failure issue and the domain controller restart issue. OOB updates released for other supported Windows Server versions address only the domain controller restart issue.
For complete guidance and installation instructions, see the relevant KB articles:
Standard Windows updates
- Windows Server 2025: KB5091157 (OS Build 26100.32698) Out-of-band
- Windows Server, version 23H2: KB5091571 (OS Build 25398.2276) Out-of-band
- Windows Server 2022: KB5091575 (OS Build 20348.5024) Out-of-band
- Windows Server 2019: KB5091573 (OS Build 17763.8647) Out-of-band
- Windows Server 2016: KB5091572 (OS Build 14393.9062) Out-of-band
Windows hotpatch updates
- Windows Server 2025 Datacenter: Azure Edition: Hotpatch KB5091470 (OS Build 26100.32704) Out-of-band
- Windows Server 2022 Datacenter: Azure Edition: Hotpatch KB5091576 (OS Build 20348.5029) Out-of-band