Microsoft fixes 24-hour email outage by restarting servers in stages

Microsoft resolved a 24-hour outage of its cloud-based email and scheduling services by restarting affected servers in stages, after a core process became overwhelmed and triggered automated shutdowns. The incident disrupted services for over 450 million paid user licenses and one billion connected devices. The outage, one of the longest in Microsoft's history, hit Exchange Online features, leaving users unable to send emails, manage calendars, or host virtual meetings. Downdetector logged over 7.4 million reports, peaking at nearly 20,000 per minute. Engineers had to gradually restore servers to avoid overwhelming them with a huge backlog of queued messages, a process taking hours to days. Global insured losses from the incident are estimated between US$300 million and $500 million, according to Morningstar DBRS. Experts called the outage a wake-up call for businesses to maintain backup systems, such as alternative email accounts and software redundancy, while some suggested governments should be able to fine tech firms for productivity losses.