Microsoft 365 went down around the world on Thursday evening, 12 November, and it was still not fully fixed on Friday morning. Outlook stopped working for many users — mailboxes would not open and emails were delayed — and parts of Teams, including calendars and scheduling, stopped working too. Microsoft said a large number of its servers had unexpectedly become unavailable after failing automated health checks, which overloaded the servers still running.
At the peak, the outage tracker Downdetector logged more than 130,000 reports of Outlook problems in the US alone, around 1pm Eastern time on Thursday — user reports, not a count of affected accounts, so the real number hit is higher. The disruption spread to 74 countries and territories, and by Friday morning Microsoft was still reporting only “marginal success” in bringing services back, with no time given for full recovery. Its own service health notices track the incident as EX1550543 (Exchange Online) and MO1550821 (Microsoft 365).
Why this matters beyond the headlines
For most small businesses, Microsoft 365 is not one tool among many. It is email, calendar, chat, files and meetings in a single subscription. When it goes down, quotes do not go out, invoices do not get paid, customer replies sit unsent and meeting invites fail. Electric truck maker Workhorse Group even rescheduled its quarterly results to Monday 16 November, citing business disruption from the outage.
There is a second effect that gets less attention. When a customer cannot reach you by email, the first thing they do is search for you. They look up your phone number, your opening hours, whether you are open today. If your Google Business Profile has an old number, or your website buries your phone number, that customer tries the next business. An outage is the day your public business information earns its keep.
One honest note: Microsoft says there is no indication this was a cyberattack, and it was not caused by a surge in users. A large group of servers failed their health checks at once, and the fix — bringing servers back in stages and rolling back a recent network configuration change — has not gone smoothly. Microsoft has promised a full post-incident report once service is restored; until then the cause is unconfirmed.
What a UK small business should do about it
First, do not try to fix it yourself. Do not reinstall Office, delete your Outlook profile or reset your password. None of that helps when the fault is on Microsoft’s servers, and it can create new problems once service returns. Check Microsoft’s own status page at status.cloud.microsoft before changing anything on your computer.
Second, tell your customers another way. Pick up the phone or send a WhatsApp or text, and say your email is down so they do not sit waiting on a reply that is not coming. A one-line notice on your website or Google Business Profile, with a phone number, is enough.
Third, be alert for scams. Outages attract fake “Microsoft support” calls and links promising to fix your mailbox for a fee. Microsoft will not ring you to ask for your password.
Fourth, when this is over, write a one-page plan for next time. You do not need a second email system — just a written answer to one question: how do we reach staff and customers when Microsoft 365 is down? A phone list, a WhatsApp broadcast group and an offline copy of key contacts go a long way. Test it once rather than filing it and hoping.
And while you are at it, check what a customer finds when they search for you. Open Google and search for your business name, then ask ChatGPT or Perplexity for the best business in your trade in your town. If your phone number is wrong, your hours are out of date or you do not appear at all, fix it before the next outage. This is the work our GEO services cover — making sure customers find the right details about your business when they search. Our free Visibility Audit shows where you rank on Google, whether AI tools cite you, and whether your business details are correct — with what to fix first.
Frequently asked questions
Is the Microsoft outage a cyberattack?
Microsoft says there is no indication of malicious activity, and the pattern does not fit a typical attack: overall traffic did not rise, and no group has claimed responsibility. Microsoft says a large number of its servers became unexpectedly unavailable after failing automated health checks; the full cause comes with its post-incident report.
Before you spend anything, our free Visibility Audit shows where you rank on Google, whether AI tools like ChatGPT cite you, and whether you win AI answers — with what to fix first. Free, with no obligation.