Microsoft 365 outage hits European users as Office 2021 LTSC support ends

Microsoft’s Global Secure Access (GSA) service suffered a multi-hour outage on 13 October 2026, preventing European customers from accessing core Microsoft 365 applications. The incident occurred as the company ended support for Office 2021 Long-Term Servicing Channel (LTSC), its final on-premises Office release, adding pressure on enterprises to migrate to cloud-based alternatives or upgrade to Office LTSC 2024. Microsoft did not disclose the root cause of the GSA failure but acknowledged that a segment of its infrastructure was operating below performance thresholds, disrupting connectivity to Outlook, Teams, OneDrive, SharePoint Online, and Windows 365 Cloud PCs. The timing amplified frustration for businesses already evaluating their Office deployment strategies, as the outage underscored persistent reliability concerns with Microsoft’s cloud services at a critical decision point for IT teams.

What happened

Microsoft reported the GSA outage on its Service Health Status page, though the company’s own admin portal was partially affected, delaying status updates for customers. The initial notice stated that administrators might be unable to access the Microsoft 365 admin center to check service health, creating a feedback loop where users were left without official communication channels. Microsoft later confirmed that traffic and performance optimizations were underway, and the system began showing signs of recovery after several hours. The company did not provide a specific timeline for full restoration or details on the number of affected users, but the incident was limited to European customers using GSA to access Microsoft 365 services.

The outage coincided with the end of support for Office 2021 LTSC, which reached its five-year lifecycle on the same day. Microsoft has positioned Office LTSC 2024 as the next on-premises option for customers unwilling or unable to adopt Microsoft 365, though the company has increasingly framed cloud migration as the preferred path. The overlap of the outage and the support deadline placed additional scrutiny on Microsoft’s messaging, as enterprises weighing compliance and security requirements were forced to consider whether the cloud’s reliability matched its promised benefits.

Why it matters

For enterprises still relying on on-premises Office deployments, the end of support for Office 2021 LTSC removes a key compliance and security safety net. While the software will continue to function, Microsoft will no longer provide security updates, bug fixes, or technical support, leaving organizations exposed to unpatched vulnerabilities. The outage further complicates the decision-making process for IT teams, as it highlights the trade-offs between on-premises control and cloud resilience. Microsoft’s repeated service disruptions—this incident being the latest in a series—have eroded confidence in the reliability of its cloud infrastructure, particularly for mission-critical workflows.

The incident also raises questions about Microsoft’s ability to manage its growing portfolio of cloud services. GSA, which acts as a secure access layer for Microsoft 365, is a relatively new addition to the company’s enterprise offerings, and its failure suggests potential scaling or architectural challenges. For customers already skeptical of cloud dependency, the outage provides ammunition to delay or reject migration plans, opting instead for hybrid or alternative solutions. Meanwhile, Microsoft’s competitors in the productivity and collaboration space may seize on the disruption to pitch their own platforms as more stable alternatives.

What to watch

Microsoft has not yet disclosed whether the GSA outage will prompt a post-incident review or compensation for affected customers. Enterprises will be monitoring the company’s response, particularly any changes to service-level agreements (SLAs) or financial credits for downtime. Additionally, the end of support for Office 2021 LTSC may accelerate migration timelines for organizations that had been delaying the transition, though the outage could equally push some to explore third-party support options or alternative productivity suites.

The broader industry impact will depend on how Microsoft addresses the reliability concerns raised by this incident. If similar outages continue, it could strengthen the case for multi-cloud or hybrid strategies among enterprises, reducing dependency on a single provider. For now, IT teams are left to weigh the risks of on-premises obsolescence against the demonstrated instability of Microsoft’s cloud services, with no clear resolution in sight.