Microsoft Outage Hands Fax Machines a Comeback

A global Microsoft outage has pushed parts of Japan’s financial sector back to an old tool. Market participants switched to fax after Outlook email, used to confirm trade details, stopped working.

The disruption began on Thursday and hit Microsoft 365 business apps such as Teams, SharePoint and Copilot worldwide, along with Outlook. In the US, Downdetector logged up to 130,000 Outlook reports at the peak.

How the Microsoft Outage Hit Japan’s Finance Sector

Nikkei reported that the outage disrupted Japan’s financial market. A source on a domestic asset manager’s trading desk said one broker had asked it to stop placing orders. That broker relies on Microsoft’s email system.

In addition, investment trusts delayed publishing their net asset values. The government’s shared IT system, overseen by the Digital Agency, also went down, Deputy Chief Cabinet Secretary Masanao Ozaki confirmed.

The root cause remains unclear. Microsoft says servers failed automated health checks, while a core process that sets up secure connections became overwhelmed.

Servers that came back online often failed again once traffic returned, the company adds. Its Japanese unit said it had found no facts pointing to a cyberattack.

Japan was not alone. In Australia, some workers also turned to fax machines, ABC reported. RSM Australia partner Ashwin Pal estimated the cost to local businesses in the billions of Australian dollars.

We're continuing to work on recovering our frontend servers while implementing further traffic optimization actions to improve service stability and increase capacity. A more comprehensive update can be found at MO1550821 in the Microsoft 365 admin center, as well as…

— Microsoft 365 Status (@MSFT365Status) November 13, 2026

The Microsoft outage follows a string of failures at central tech providers. In September, a separate outage took down ChatGPT, Claude and Grok. For crypto, the pattern also revives the debate about Web3’s centralization problem.

Wall Street Takes the Disruption in Stride

Japan still has a domestic fax industry. Brother, Canon and Ricoh continue to sell fax machines and printers with fax features. Even so, fax is no longer a core business for any of them.

Meanwhile, Microsoft shares closed slightly higher on Thursday despite the outage, then slipped in overnight trading. The stock was already under pressure after Microsoft overtook Nvidia in market value earlier this week.

Still, a Microsoft outage of this scale shows how fragile financial plumbing can be. A single point of failure can freeze key systems, as a cooling failure at a CME data center showed last year.