Microsoft Outage Hands Fax Machines a Comeback

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.

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

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

Return to Analog Tools

Market participants in Japan switched to fax after Outlook stopped working, a move that highlights the sector's reliance on email for trade confirmations.

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

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.

Cause and Aftermath

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.

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.