A Microsoft 365 outage that began shortly before 18:00 Irish time on Thursday 12 November left many users worldwide without Outlook email, with parts of Teams, SharePoint Online and Copilot also hit. As of 07:15 Irish time on 13 November, Microsoft reported only partial recovery and gave no time for a full fix.
- What: an outage centred on Exchange Online, the service behind Outlook mailboxes.
- Incident IDs: EX1550543 (Exchange Online) and MO1550821 (Microsoft 365), in the Microsoft 365 admin centre.
- Cause so far: Microsoft says servers became unexpectedly unavailable, straining the rest. It says it is not aware of malicious activity.
- Ireland: Irish users were affected, but we found no report of a named Irish hospital, HSE service or company being disrupted.
What happened
Microsoft's Microsoft 365 Status account on X first said it was investigating problems accessing Exchange Online mailboxes "through multiple connection methods in the Americas", under incident EX1550543. Shortly afterwards it widened the warning, saying the issue may affect Microsoft 365 connectivity for users in any region, and opened a second incident, MO1550821.
Microsoft first blamed "elevated load across multiple regions". It later said: "We determined the elevated load isn't driven by an increase in traffic, but by a number of servers being unexpectedly unavailable; straining the remaining infrastructure." Microsoft also said a process on the affected servers "responsible for establishing secure connections becomes overwhelmed", and that it had paused deployments and was restarting servers.
Affected services include Outlook, Teams calendars and scheduling, SharePoint Online, Microsoft 365 Copilot, Defender XDR, Intune, Planner and Purview, according to Microsoft's notices as reported by UC Today. Teams calls and chat largely worked.
Current status
Recovery has been uneven. At about 21:00 Irish time on Thursday, Microsoft said it had "validated an alternative service health check method" that brought some servers back, CNBC reported. Around 23:00 it said a portion of servers were back "and they remain stable so far", but later warned that returned servers "can become unresponsive again once they receive traffic", according to ABC News.
Shortly after 04:30 Irish time on Friday, Microsoft said: "We're observing partial recovery across regions in which we've applied these adjustments." By about 06:30 it was evaluating traffic controls to "increase capacity and stability", ABC News (Australia) reported. Microsoft said: "As of now, we are not aware of any malicious activity that is causing this incident." It has promised a post-incident report once the problem is fixed.
As of 07:15 Irish time on 13 November, we could find no Microsoft statement that service was fully restored. Check status.cloud.microsoft or your Microsoft 365 admin centre for the latest position.
Is Ireland affected?
Yes, for at least some users. TheJournal.ie reported on Friday morning that Outlook, Teams and other Microsoft services were still down for users around the world, with outage maps showing problems in parts of Europe. It did not name any affected Irish organisation.
At the time of writing we found no statement from the HSE, an Irish hospital, GP service or pharmacy body, and no RTÉ, Irish Times, Irish Independent or Silicon Republic report on Irish impact. Microsoft has a campus in Leopardstown, Dublin, and data centre operations in Ireland, according to the Department of Enterprise. Nothing we found links the outage to its Irish sites.
What it means for hospitals and life-science firms
Health services elsewhere felt the outage. In Toronto, Unity Health Toronto declared a Code Grey, which signals an infrastructure failure, and said: "Please be advised that patient and resident care is not affected by the outage." University Health Network said: "There is no impact on patient care delivery," CP24 reported. In Australia, Canberra Health Services reported problems with email, voicemail and some faxes but "no known impacts to clinical care", according to ABC News.
For hospitals, labs, manufacturers and clinical trial teams that rely on Outlook and Teams, the lessons are practical:
- Keep an offline or printed contact list for key staff, suppliers and regulators.
- Agree a fallback channel that does not depend on Microsoft 365, such as phone trees or a separate messaging tool.
- Have paper or downtime procedures for anything time-critical, such as batch release sign-offs, deviation reports and trial safety reporting.
- Check the official status page before changing settings or resetting accounts. During a provider outage, local "fixes" can create new problems.
How to stay safe
Big outages are a gift to scammers. During the July 2024 CrowdStrike outage, the US cyber agency CISA said it had "observed threat actors taking advantage of this incident for phishing and other malicious activity." We have seen no report of a scam campaign tied to this outage, but the same risk applies:
- Don't click links in unexpected emails or texts about "restoring your mailbox" or "re-verifying" your account.
- Check status only at official pages: status.cloud.microsoft or your organisation's admin centre, typed in yourself.
- Never give your password in reply to a message. Microsoft says it "will never proactively reach out to you to provide unsolicited PC or technical support."
- Treat password-reset requests with suspicion if you didn't ask for one. Ireland's National Cyber Security Centre (NCSC) says: "if in doubt, don't click and report it to your account provider."
- Report it: forward suspicious work emails to your IT team. The NCSC says phishing scams should be reported to An Garda Síochána at your local Garda station, and reports can also be sent to phishing@ncsc.gov.ie.
FAQ
Is Outlook down?
As of 07:15 Irish time on 13 November, Microsoft had reported partial recovery but not a full fix. Check status.cloud.microsoft for the latest.
Is Teams down?
Partly. Calendars and meeting scheduling were hit; calls and chat largely worked.
Was it a cyber attack?
Microsoft says it is not aware of any malicious activity causing the incident. It has not yet published a root cause.
Has the HSE been affected?
We found no HSE statement at the time of writing. Priya Life Science will update this article if one is published.
Sources
- Microsoft 365 Status on X, post on EX1550543 and post on the cause (EX1550543, MO1550821), 12 November 2026
- Microsoft, Microsoft 365 service health status
- CNBC, Widespread Microsoft outage takes down Outlook and other 365 services, 12-13 November 2026
- ABC News, Microsoft Outlook outage stretches on for hours, 13 November 2026
- ABC News (Australia), Live: Microsoft outage affects users worldwide, 13 November 2026
- UC Today, Microsoft 365 Outage: Outlook Down, and the Fix Won't Hold, 13 November 2026
- TheJournal.ie, Outlook, Teams and other Microsoft services still down this morning as global outages continue, 13 November 2026
- CP24, Microsoft outage impacts some Toronto hospitals, City of Toronto, post-secondary institutions, 12 November 2026
- CISA, Widespread IT Outage Due to CrowdStrike Update, 19 July 2024
- National Cyber Security Centre (Ireland), Quick Guide: Phishing and Quick Guide: QR Code Phishing & Scams, January 2025
- Microsoft Support, Avoid tech support scams
- Department of Enterprise, Microsoft announces the creation of 200 engineering roles, 23 November 2020
Cover image: AI-generated illustration of a Microsoft shop front on a European street. It does not show a real location or real people.
