The British technology publication The Register reported the change on 10 November. Microsoft will enable Claude on 9 December in tenants whose administrators have not yet chosen a setting, the publication said. If an administrator does not change the setting, the tenant is included.

Microsoft’s help page says Anthropic acts as a Microsoft subprocessor in Copilot, meaning it processes customer data on Microsoft’s behalf and under its oversight. Claude use is then covered by Microsoft’s Product Terms and Data Protection Addendum (DPA). Claude is already on by default for most Microsoft commercial cloud customers. The exceptions are the EU, EFTA countries and the UK. The models are available in Microsoft Copilot, Researcher, Copilot Studio, Power Platform and Copilot in Microsoft 365 apps, among others.

The Register says data is processed in the United States

The Register said Microsoft is making the change in the UK because the country is not in scope of Microsoft’s EU Data Boundary. The boundary is Microsoft’s commitment to process EU and EFTA customers’ data within the region.

Microsoft’s help page states that Claude models are currently excluded from the EU Data Boundary and from in-country processing commitments. Citing Microsoft’s documentation, The Register reported that Anthropic processes the data in the United States.

Microsoft last updated the help page on 4 November. It still lists the UK as a region where Claude is off by default. The page does not mention the December change, so the date comes from The Register.

Microsoft is also retiring the setting that restricts Claude to Microsoft 365 apps alone, the publication said. The help page says this setting became available to EU, EFTA and UK customers in April 2026. The Register did not say when the setting will be removed.

How administrators can block or restrict access

Administrators can switch Claude off in the Microsoft 365 admin center under Copilot > Settings > AI providers operating as Microsoft subprocessors by selecting Disable Anthropic as a Microsoft subprocessor. The change requires the AI Administrator or Global Administrator role. On the same page, administrators can also restrict access to specific users or Entra ID security groups. Microsoft says the restriction applies to both Microsoft Copilot and Copilot Studio.

The default setting does not enable Anthropic models that require Anthropic to retain data (Anthropic models with Data Retention), such as Fable 5.0 and Mythos 5. The help page says these models are off by default everywhere; to use them, an administrator must switch them on separately and accept Anthropic’s commercial terms and data protection addendum. When these models are used, Anthropic retains most inputs and outputs for up to 30 days. It may keep content classified as a potential violation of its Usage Policy for up to two years.