What caused the global outage at Microsoft

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The global outage at Microsoft, which began on July 19, 2024, was primarily caused by a combination of issues related to a configuration change in Microsoft’s Azure backend and a problematic software update from CrowdStrike, a cybersecurity provider.

Key Causes of the Outage

1. Configuration Change in Azure: Microsoft identified a configuration change within its Azure cloud services as a significant factor leading to connectivity failures between storage and compute resources. This disruption affected various Microsoft 365 applications, making them inaccessible to users worldwide
2. CrowdStrike’s Software Update: Concurrently, a defect in a software update from CrowdStrike’s Falcon sensor, which is widely used for cybersecurity on Windows devices, exacerbated the situation. Many users experienced the “Blue Screen of Death” (BSOD) and were unable to reboot their systems. CrowdStrike acknowledged the issue and confirmed that it was aware of the crashes related to its software.

Impact of the Outage

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The outage led to widespread disruptions across multiple sectors, including airlines, banks, and media outlets. Major airlines grounded flights, and numerous businesses faced operational challenges due to the inability to access critical systems and applications[2][3][4].

Microsoft is actively working to mitigate the effects of the outage and restore services, with reports indicating gradual improvements in service availability as efforts progress