Microsoft Issues Emergency Patches for Windows Server After April Update Glitches
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REDMOND, Wash. (AP) — Microsoft released emergency security updates Tuesday to address critical failures affecting Windows Server systems following the installation of its April 2026 monthly security patch.
The out-of-band fixes target a range of severe issues that have disrupted enterprise operations globally. Problems include installation failures that prevent systems from booting, domain controller restart loops, and unexpected BitLocker recovery prompts that lock users out of encrypted drives.
The updates were issued shortly after 8:35 a.m. ET on April 20, 2026. Microsoft stated the patches are necessary to resolve bugs introduced during the April 2026 security update cycle. The company advised administrators to apply the new patches immediately to restore system stability.
Affected systems include various versions of Windows Server. The issues have been reported across multiple sectors, with IT administrators noting that servers failed to complete the April update process or became unresponsive immediately after installation. In some cases, domain controllers entered continuous restart cycles, disrupting network authentication services.
Microsoft's advisory highlighted that the problems stem from specific components within the April update package. The emergency patches are designed to roll back the faulty changes while maintaining the security protections intended by the original update. The company emphasized that the new updates do not reintroduce the vulnerabilities addressed in the April patch.
Enterprise customers have been urged to review their server environments for signs of the reported issues. IT teams are advised to check for error logs related to installation failures and BitLocker recovery prompts. Microsoft provided detailed guidance on its support website for administrators managing the remediation process.
The incident marks a significant disruption for organizations relying on Windows Server infrastructure. The timing of the failures, occurring shortly after the standard monthly update release, has raised concerns about the testing protocols for critical security patches. Microsoft has not yet commented on the root cause of the bugs or the timeline for their discovery.
Administrators are advised to monitor their systems for any residual issues after applying the emergency patches. Microsoft has indicated that further updates may be necessary if additional problems are identified. The company is working with affected customers to resolve outstanding issues and prevent future occurrences.
The situation remains under review as IT teams worldwide assess the impact of the April update and the effectiveness of the emergency fixes. Microsoft has not provided a full timeline for the resolution of all reported issues, leaving some uncertainty about the long-term stability of affected systems.