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Microsoft fiber foul-up cut off Azure California for almost five hours
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Fusion42 · 24 July 2026 · Fusion42 review
A bug in Microsoft's maintenance automation system incorrectly removed network routes from additional devices during routine fiber maintenance, severing Azure West US region from its wide-area network for nearly five hours and degrading 27 services. The outage was resolved by rolling back the changes; Microsoft's safety checks failed to catch the routing error before impact.
This Wire brief sits within Fusion42's coverage of Enterprise Software, and 5 sources have reported it between 24 Jul 2026 and 25 Jul 2026.
◆ ◆ The Wire takeaway
If you're running on Azure West US, your safety isn't a second network path—it's the automation that's supposed to verify it before touching either one. Microsoft's bug proves that conversion layer is a single point of failure; you need to test your own failover to a different region, not trust their checks.
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5 sources · first reported 24 Jul 2026 · latest 25 Jul 2026
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