Microsoft declares end to the Outlook and Teams outage that hit users in 74 countries

Fax machines ran while Outlook sat dark

Foreign banks in Taipei went back to fax machines to reach overseas headquarters. Britain's National Health Service returned to paper records, and Euronext, the European exchange operator, told listed companies to phone in their trades ¹. Norway's parliament lost email, and 80 to 90 Danish municipalities were reportedly hit ¹.

One vendor, 74 countries, 7.4 million reports

The failed plumbing belonged to one vendor: Microsoft's▼−0.28% — Microsoft, down 0.28 percent today Outlook, Teams and Copilot, its AI assistant, with more than 450 million commercial subscribers and users hit in 74 countries, a concentration customers price at every renewal ¹. It broke with Exchange Online, the email service, at about 11:17 a.m ²¹. Eastern on Thursday, November 12 ²; Microsoft declared full recovery on Saturday, November 14 ¹. Downdetector, an outage-tracking site, logged more than 7.4 million reports↗, a report count, not a user count ². For the whole outage, institutions ran on channels that predate the cloud.

Microsoft's own upgrade did the damage

The company's account: an earlier network capacity upgrade surfaced after a later network change, backend servers became unavailable, and restarts failed under returning traffic ². "This was a technical issue not related to cyber or AI/agents," Microsoft said, promising a full post-incident report↗ ³. It was the second Microsoft service disruption of 2026 ¹.

The stock closed Friday mostly flat on a slightly lower Nasdaq, at a value above $3.8 trillion ¹. The operating losses sat with customers: hospitals ³, rail operators across Germany, Britain and Canada ¹, airlines that lost touch with passengers ³, and the US House of Representatives ¹. The Pentagon sits on the same rail, under a $9.7 billion deal that includes Microsoft 365 ¹.

The next day, the sky closed too

On Friday afternoon the Federal Aviation Administration halted every US departure at 3:54 p.m ⁴⁵⁶. Eastern ⁴ and lifted the stop at 8:15 p.m., the longest nationwide grounding since September 11, 2001, and two weeks before Thanksgiving ⁵⁶. More than 7,000 flights were canceled before the stop lifted, and more than 3,600 more fell by Saturday morning ⁴⁵.

Transportation Secretary Sean Duffy blamed 1980s copper lines and aging switches overloaded as new equipment went in; the new IP switches held, he said ⁷. Homeland Security Secretary Markwayne Mullin ruled out any Microsoft connection and cited "zero evidence" of a cyberattack, though nothing was "completely certain" ⁷.

The blame lands on routers built between 2001 and 2006

CBS News, cited by Yahoo News, reported the FAA's preliminary investigation↗ points to Cisco▼−7.54% — Cisco, down 7.54 percent today 600-series routers built between 2001 and 2006, on a private network run by L3Harris▼−3.91% — L3Harris, down 3.91 percent today ⁵. A Transportation Department rule that took effect on October 19 puts "government system failures" outside airline control, so stranded passengers are owed a refund only if they give up the trip ⁵.

The $50 billion question in Congress

Duffy ruled out SMART, the FAA's AI traffic planner, held under a 12-year, $875 million contract with Boston-based Air Space Intelligence ⁷. Mullin said President Trump had declared the situation a national emergency, and Duffy asked Congress for $50 billion on top of the $12.5 billion already approved over five years ⁷⁴. AT&T▼−0.13% — AT&T, down 0.13 percent today holds the FAA telecom lead on an initial $74.3 million award from August, targeted to finish by the end of 2028 ⁷.

Without the money, Duffy warned, "you will have more of them" ⁵. Microsoft said Friday that "we know the trust they place in our services" ⁸; customers are owed the post-incident report ³. Two outages in one year hand rivals a redundancy argument at renewal time, and a flat stock suggests the market has not priced the next one.