On Monday 1 June 2026, some Microsoft 365 users could not open files in Office for the web or Microsoft Teams. Microsoft tracked the issue as MO1329446 and said the impact was later resolved. The next day, Exchange Online suffered a separate mail-flow incident that caused delayed or failed email delivery for affected customers across several regions, including Europe.
Neither incident was a business-ending disaster. Both raised the same practical question: when the cloud service your team depends on has a problem, can people still work?
This is the part worth taking seriously. Cloud services are reliable overall, but outages and service degradations still happen. The useful question is not whether Microsoft 365 is good enough. It is whether your business has sensible fallbacks when a service you rely on stops working for an hour, an afternoon or longer. That is the same single-supplier lesson that ran through the disruption at M&S and Co-op, scaled down to an ordinary working day.
The cloud is not a continuity plan on its own
“It is in the cloud” is not a continuity plan. It is a delivery model. Cloud platforms remove a lot of infrastructure burden, but they can also remove older fallbacks without anyone noticing.
When files lived mainly on a local server, a cloud outage was less likely to stop a user opening a desktop copy. Now, many teams rely on managed Microsoft 365 services, SharePoint, OneDrive, Teams and Exchange Online for almost everything. If a Microsoft service has an issue, the whole office can feel it at once.
The fix is not to abandon Microsoft 365. It is to keep a few escape routes ready.
When the cloud blinks: what keeps you working
| If this fails | What it can stop | Practical fallback |
|---|---|---|
| Office for the web | Opening and editing shared documents | Keep critical files synced for offline use |
| Teams | Chat, calls and meetings | Agree a second communication channel in advance |
| Exchange Online | Sending and receiving email | Keep phone numbers and mobile access ready |
| Sign-in or identity | Access to multiple Microsoft services | Keep an escalation route outside Microsoft 365 |
| SharePoint | Shared libraries and intranet access | Keep essential working documents available locally |
Start with offline access. OneDrive can sync selected files and folders so people can keep working on the documents they actually need. This is one of the Office 365 features people tend to overlook, and it is worth setting up before you need it. Knowing where your files really sit across SharePoint and shared libraries makes that planning easier.
Then sort communications. If your only way to tell staff that Teams is down is a Teams message, you do not have a fallback. Agree a second channel in advance, whether that is phone, SMS, WhatsApp for urgent operational use, or another approved system. Make sure key staff can access email on a mobile device too. For iPhone users, it only takes a few minutes to set up on iOS.
Watch the security angle
Outages are a gift to attackers. After a public service issue, phishing emails often appear claiming that Microsoft 365 access has been suspended, files need to be restored or passwords must be reset. Stressed staff are more likely to click.
Good anti-phishing defences help, but a quick internal warning also matters. Tell staff what has happened, where updates will come from and what not to click. Stolen-credential alerts can also help if a login has already leaked. The same calm approach applies to wider network security basics. An outage is not the moment to discover that your foundations are weak.
Know where to check
When something breaks, check the right place. Microsoft says administrators should use Service health in the Microsoft 365 admin centre to see tenant-specific service issues. If admins cannot sign in, Microsoft’s public Service health dashboard can show known issues affecting access.
The bigger job is mapping which processes depend on which Microsoft services. Payroll, quotes, customer support, shared files, approvals and management meetings may all rely on different parts of Microsoft 365. If you run several sites, support for international teams and IT cover for your European offices can keep that plan consistent.
If you are still moving into the cloud, weigh resilience alongside the wider Microsoft 365 pricing and security changes, because good cloud migration planning shapes how gracefully you cope with the next outage.
Frequently asked questions
Was Microsoft 365 down in June 2026?
Yes. On 1 June, some users could not open files in Office for the web or Teams. On 2 June, Exchange Online had a separate mail-flow incident affecting email delivery for some users.
How do I check if Microsoft 365 is down?
Use Service health in the Microsoft 365 admin centre for tenant-specific information. If you cannot sign in, check Microsoft’s public status page.
Does Microsoft back up my data?
Microsoft provides built-in resilience and offers Microsoft 365 Backup, but businesses still need to plan for accidental deletion, corruption, ransomware and recovery requirements.
What should we do before the next outage?
Set up offline file access, agree a second communication channel, document escalation contacts and test your recovery plan.
Build the plan before the next outage
Cloud outages are not a reason to panic or retreat from Microsoft 365. They are a reason to know where your seams are before one of them tears. If you would like a simple continuity plan that keeps your team working when files will not open, from offline copies to a tested fallback for communications, talk to the team at Northern Star and we will help you put the escape routes in place.
