Microsoft 365 outage checklist for email, Teams and Copilot

Microsoft’s global outage began Thursday, November 12, and as of Friday, November 13, it still isn’t fully fixed. Exchange Online email is the center of it, and Teams, Copilot, SharePoint Online and Defender XDR are caught up in it, according to Microsoft’s admin advisory MO1550821. If your business runs on Microsoft 365, the practical question is what your team does while mail is stuck.

What is down, and what still works?

Email is the broken piece. Exchange Online mailboxes have been hard to open in Outlook on the web, desktop and mobile, and messages can be delayed. Features that depend on Exchange or email inherit the problem. Parts of Teams, SharePoint and Copilot that don’t rely on Exchange keep working, per MacRumors and SecurityWeek.

In practice, most Teams calling, meetings and messaging still works. Scheduling meetings, handling invitations and editing calendar entries can throw errors, and some contact and channel management features are affected. Files stored directly in SharePoint remain accessible. Copilot chats may fail, and Copilot may be unable to pull work email, calendars or files. Microsoft also reported trouble with Planner, To Do, admin tools and some SharePoint functions.

Switching mail apps won’t help. MacRumors reported that Exchange accounts opened in Apple Mail were affected too, because the fault sits in Microsoft’s infrastructure rather than in Outlook. SecurityWeek also reported that some Google Workspace users had trouble reaching Google-hosted mail through the Outlook desktop and mobile apps. No other outlet has confirmed that.

What should you do in the first hour?

Confirm the problem is Microsoft’s, tell your people, and move time-sensitive work off email. Don’t reset passwords or rebuild Outlook profiles for a fault that sits on Microsoft’s side. A short list covers most of it:

• Check the incident IDs. Microsoft tracks the Exchange Online problem as EX1550543 and the wider outage as MO1550821. Both are listed as service degradations. Match what your users see against those before you touch anything on your end.
• Tell staff through a channel that isn’t email. Teams chat is mostly working, so use it, and add a text or phone message for anyone who doesn’t live in Teams.
• Run meetings the simple way. Since scheduling and invitations are the shaky part, share meeting links by chat or phone instead of waiting on calendar invites.
• Work from SharePoint files. Files stored directly there remain accessible, so point people at the documents they need rather than at attachments sitting in stuck mailboxes.
• Don’t lean on Copilot. If it can’t reach email, calendars or files, summaries and drafts built on them will fail. Have a manual route for anything due today.
• Phone the people who matter. Invoices, customer notices and anything legal should go by a call, with the email as a follow-up.
• Start a log. Note when your users first hit problems and what broke. Microsoft logged the incident start at 1:26 PM ET Thursday. Whether it will offer SLA credits hasn’t been reported, but your own record will help if it does.

How long will delayed email be held?

Microsoft extended its email timeout window to 48 hours, according to MacRumors and The Verge, so delayed messages are kept while backlogs clear. That buys time, but it isn’t a guarantee. Microsoft hasn’t said how the 48 hours is counted or what happens to a message that misses it.

Treat the window as a clock. For anything important, confirm receipt by phone rather than trusting that a delayed message will turn up. Resist the urge to resend everything, because duplicates will land in a flood once the backlog moves. After service settles, check shared mailboxes and sent items for gaps, and ask key customers whether anything from the last two days never arrived.

Don’t assume recovery will be a clean switch either. Microsoft warned it would be gradual as apps reconnect. Later on Friday, it said repairs in parts of Asia Pacific were improving mailbox access and moving delayed email through, with the work being extended to other regions and intermittent failures possible.

Keep one channel that doesn’t run through Microsoft

Teams held up better than email this time, but it isn’t a safe fallback by itself. Earlier on Thursday, a separate Teams incident, TM1550488, caused message delays, conversation errors and trouble retrieving chats for users in North and South America. It started at 9:45 AM ET and ended at 10:53 AM. Microsoft blamed resource contention and says that incident is resolved. It hasn’t said whether it’s related to the afternoon outage.

Pick a second route for staff and for customers now, before you need it. A group chat on a consumer messaging app works for a small team. If you need to bring in outsiders on a call, our comparison of WhatsApp guest calling and FaceTime links covers two options that don’t need a Microsoft account. Keep a current list of staff and client phone numbers somewhere that isn’t your mailbox. A portable drive such as the Samsung T7 Portable SSD is a simple place to hold an offline copy of that list and your most important documents.

The same habit applies whenever a service you rely on gets shaky or goes away: keep your own copy, as we said about the Apple Support Community closing.

Why this matters for your business

One fault took out email, calendars and Copilot’s access to them at the same moment. That is what depending on a single vendor looks like on a bad day. The scale was large: MacRumors, citing the Associated Press, reported nearly 130,000 Outlook reports on Downdetector shortly after 1 p.m. ET Thursday, and TechSpot cited nearly 150,000 reports spanning several Microsoft apps, including Outlook, Teams and Copilot. Those are user-submitted report counts, not a measure of affected customers, and the two outlets don’t agree.

The spillover reached beyond Microsoft’s own apps. TechSpot reported that Anthropic and OpenAI said they were investigating severe connectivity problems with Microsoft services that hit some of their productivity tools. No other outlet confirms that wording, so take it as reported rather than established. If your team uses AI tools connected to Microsoft accounts, they share the same single point of failure.

On security, Microsoft’s status page said it had no evidence of a cyberattack:

“At this time, we have no evidence of malicious activity associated with this incident” (Microsoft, via SecurityWeek).

That doesn’t settle the cause. But it means your priority is keeping work moving, not hunting for a breach. If you handle sensitive records, plan for vendor-side failures the way clinics had to think through the Quest Diagnostics data breach: assume the problem will start somewhere you don’t control.

My view: write your continuity plan this week, not after Microsoft’s postmortem arrives. The plan above takes an hour to draft and costs nothing but attention.

What Microsoft hasn’t explained yet

The root cause is unconfirmed, and Microsoft’s explanation has shifted. Early updates blamed elevated load across multiple regions. Later updates said the load wasn’t from extra traffic but from servers becoming unexpectedly unavailable, and that a process that sets up secure connections was overwhelmed. SecurityWeek reported that Microsoft had started undoing a recent change to its network configuration, while TechSpot and BleepingComputer described it as still investigating whether reverting recent configuration updates could speed recovery.

Mark Gregory, an associate professor at RMIT University, told The Guardian, as relayed by TechSpot, that the fault likely sits in Microsoft’s network layer and may resemble the 2023 Optus outage. That’s outside speculation, and Microsoft hasn’t confirmed it.

Recovery reports also depend on the time. By 6:57 PM ET Thursday, Microsoft reported limited recovery, with some servers stable and traffic moved to alternate routes. TechSpot later described restored servers becoming unresponsive again once traffic returned, and Microsoft limiting some traffic types in some regions. By Friday, Microsoft hadn’t given an ETA for full restoration. Once mitigation is complete, it has promised a Post-Incident Report that covers the root cause and the defensive measures it plans to add. No date for that report has been reported.

Also unanswered: whether any mail will be lost after the 48-hour window, how many customers were affected, and whether the morning Teams incident and the afternoon outage are connected.

Frequently asked questions

Is Microsoft 365 down right now?

As of Friday, November 13, 2026, the outage was still not fully fixed and Microsoft had given no ETA. Recovery was reported as gradual, with Asia Pacific improving first and intermittent failures possible elsewhere. Check your tenant's service health for incidents EX1550543 and MO1550821.

Will I lose my emails during the Outlook outage?

Microsoft extended the email timeout window to 48 hours so delayed messages are held while backlogs clear. It hasn't said what happens to messages after that window, so confirm anything important by phone.

Was the Microsoft outage a cyberattack?

Microsoft says it has no evidence of malicious activity associated with the incident. It hasn't confirmed a root cause, and its explanation has moved from elevated load to unavailable servers and a configuration rollback.

Does Teams still work during the outage?

Mostly. Teams calling, meetings and messaging still work, per MacRumors. Scheduling meetings, handling invitations and editing calendar entries can show errors, and some contact and channel features are affected.

Sources

This article was compiled from reporting by the following outlets. Links go to the original reports.

1. MacRumors: Major Microsoft 365 Outage Continues
2. The Verge: Microsoft Outlook is still down
3. TechSpot: Microsoft struggles to restore Outlook, Teams, and other services as global outage enters second day
4. SecurityWeek: Microsoft 365 Outage Disrupts Outlook, Exchange Online and Teams
5. BleepingComputer: Massive Microsoft 365 outage disrupts Outlook, Teams, Copilot worldwide
6. Neowin: Microsoft Exchange, Outlook, SharePoint go down right after Teams outage