For many businesses, Microsoft 365 is now so embedded in daily operations that today’s disruption felt like an organisational shutdown. Suddenly, the routine tasks that we take for granted; replying to clients, checking calendars and arranging meetings, can become a challenge. It is a stark reminder of how modern businesses depend so heavily on a small number of technology providers and how quickly operational disruption can spread when one of them experiences an outage.
Similar to the CrowdStrike incident in July 2024, when a faulty software update caused widespread disruption to Windows devices, today’s Microsoft outage demonstrates how quickly disruption from a single technology provider can have such a systemic impact.
WHAT HAPPENED?
The Microsoft 365 disruption starting on 12 November 2026 has consequences extending well beyond an empty inbox. The outage has affected access to Exchange Online mailboxes and email delivery as well as other Microsoft services such as Copilot and Teams, restricting everyday business activity. The extent of disruption varies between services and users, rather than a complete shutdown of Microsoft’s applications. Disruption has been reported across healthcare, financial services, aviation, education and government.
In the UK, hospitals, GP practices, schools and MET police have experienced difficulties accessing email and other services. Internationally, government agencies in Australia and Japan have been affected, while Indian airlines have experienced disruption to email support channels and financial firms in Taiwan have reported interruptions to transactions.
The operational impact varies, losing access to Microsoft’s services does not necessarily mean an organisation’s entire operations have stopped. Nevertheless, the breadth of disruption illustrates the outage’s international and cross industry reach and how prolonged disruption has the potential to generate substantial business costs through lost productivity, interrupted transactions and additional operating expenses. The cause and full financial impact remain unclear, but Microsoft has stated that there is currently no indication that the outage resulted from a cyberattack. Early reports suggest the global disruption could generate around USD 700 million in insured losses.
RESILIENCE AND CONTINGENCY
Businesses cannot prevent an outage at an external provider, but they can take steps to reduce its impact. Identify which providers support essential operations, including dependencies hidden within other suppliers’ services. Business continuity plans should include alternative communication channels, accessing essential documentation and contact details as well as manual workarounds for critical tasks.
Critically, the plan must remain accessible if the usual system is unavailable and should be tested regularly Assess how much of the operations depend on a single provider. Whilst consolidation can improve efficiency, it can also leave a business exposed to one outage. Where practical, alternative providers can reduce that concentrated risk. Review key suppliers’ resilience arrangements, including their recovery capabilities, outage notification procedures and escalation contacts, to understand what support will be available during a disruption.
CYBER INSURANCE: WHAT IS COVERED?
A business can suffer substantial financial loss from a cyber event without an attacker entering its network and there does not need to be malicious cyber activity in order for a cyber policy to respond. System failure, such as today’s Microsoft outage, is an example of significant interruption to operations even where the business’s own systems remain operational.
Cyber policies typically include coverage for business interruption as a result of system failure. Where the failure occurs at an external provider, dependent or contingent business interruption cover may respond. However, the scope varies as some policies are triggered by any external provider while others restrict cover to Non-IT providers or even a scheduled list of suppliers.
Establishing whether Microsoft and the affected services fall within those definitions is therefore essential. Business Interruption is also generally subject to a time retention, known as a Waiting Period, which is typically 8-12 hours. The duration of the Microsoft outage means many businesses will have already exceeded their applicable waiting period.
However, businesses will still need to demonstrate and quantify financial loss directly resulting from the interruption to establish coverage. Businesses increasingly rely on a small number of key technology providers, creating concentrated risk that can leave multiple essential functions exposed to a single failure. Operational resilience must therefore sit alongside cyber security, supported by tested contingency plans and a clear understanding of critical dependencies.
Reviewing your contingent business interruption coverage is equally important to understand how it would respond to disruption at these providers. Please get in touch with our cyber team to review your existing coverage, identify potential gaps and ensure your policy reflects the services your business relies on.
Authored by:Lara Wheeler (Assistant Vice President,Acrisure London Wholesale)
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