Europe wants to be rid of Microsoft, but how?

Data, once ‘given’

Now oil of man and market

Who holds it shapes us

a haiku by Amber van Kempen

The International Criminal Court (ICC) in The Hague switched to a European alternative after it was denied access to its email, which had been supported by Microsoft, by the United States. This followed disagreements between the United States and certain judicial decisions, with the U.S. seeking to pursue action against some judges. “Whoever controls the data controls the people,” said Brenno de Winter, managing director of Vigilis Consultancy.

“Data is the new oil,” said Frank Karlitschek, co-founder and CEO of the European open-source software company Nextcloud. The largest data holders today are primarily located in Silicon Valley and China, Karlitschek noted during the Nextcloud event held on April 15. These regions host companies whose products are used worldwide, including Microsoft and TikTok.

The central theme of the day was who controls whose data. Nextcloud and its partners argue that people should be able to manage their own data, regardless of their region. They give as an example that European data should remain within the continent and that European sovereignty must be strengthened. According to Karlitschek, Europe is currently too dependent on others, particularly the United States. “Europe is falling behind, and that cannot continue,” he said. Building a platform that ensures data remains within Europe is not especially difficult, but switching service providers is. American companies such as Amazon Web Services and Microsoft often structure contracts in ways that create vendor lock-in, meaning customers depend on a single provider for products and services, making it costly or technically difficult to switch.

The complexity of international data

European privacy law and U.S. surveillance laws (CLOUD Act, FISA 702, NSLs) together create a system with pressure from both sides. European rules strictly protect personal data through the General Data Protection Regulation (GDPR), while major cloud providers such as Microsoft and Amazon Web Services remain subject to U.S. laws that can compel them to share data, sometimes without users being aware.

This leads to a situation where legal frameworks overlap. GDPR assumes that protection can be ensured through contracts, encryption, and oversight, while U.S. law allows authorities to require cooperation even if the data is stored in Europe. As a result, a certain level of dependency remains. For European citizens, this means that rights are strong on paper, but not always fully enforceable in practice. Due to secrecy requirements, it is not always visible when data is requested.

Migrating from Microsoft to Nextcloud

Integration partner Sendent and data migration company Audriga work with Nextcloud to facilitate migration from Microsoft to European alternatives. “The risks of U.S. access to European data have always existed—Trump merely made them visible,” said Richard Marx.

Digital sovereignty exists on a spectrum. Companies either deepen their reliance on Big Tech or move toward independence, but because migration is complex, many adopt a gradual approach. Nextcloud can integrate with Microsoft applications such as Teams, email, and calendars. “Large organizations have three options: start fresh in Nextcloud, migrate everything at once and retrain users, or transition gradually,” said Frank Dengler. Most choose the gradual route.

During phased migration, Sendent ensures employees can continue using familiar tools while Audriga transfers data behind the scenes. This allows users to gradually adapt to a new platform with different interfaces, shortcuts, and layouts.

The Austrian Ministry

An Austrian ministry adopted a gradual, hybrid approach, moving data step by step to domestically hosted servers. Together with Sendent and Atos Technologies Austria GmbH, it built an architecture less dependent on external platforms.

At its core is Nextcloud, hosted on-premise and therefore governed by European law. It is used for internal communication and file sharing, while Microsoft Teams is still used mainly for external meetings.

Through Sendent integrations, Outlook and Teams remain usable, but files shared via Teams are automatically stored in the Nextcloud environment. This shifts practical data control to internal infrastructure, although some Microsoft services remain in use. However, Karlitschek notes that U.S. access risks remain until all applications and data are fully migrated to European or on-premise systems.

Locked into contracts

Dinum, the French government’s digital authority, recently transitioned from Microsoft Windows to the open-source platform Linux. This was done quickly to reduce reliance on U.S. providers. While it is often said that large organizations cannot migrate all systems at once, Dengler argues otherwise: “Data migration is 80% trivial and 20% temporary solutions. Systems differ—file naming conventions can cause issues—but much of it is manageable.”

Still, switching is not always easy. “Organizations cannot simply switch overnight,” said Ellen Kok of Digitale Doetank. During the event, attendees questioned why countries like France can move quickly while others cannot. According to Kok, many Dutch organizations are locked into long-term contracts. “For some, it could take up to ten years before they can switch.” Costs are another barrier, as budgets are often already committed to existing vendors.

Nextcloud’s largest clients

Demand for Nextcloud is growing rapidly, especially in countries such as the Netherlands, Denmark, and Brazil. In absolute numbers, however, the most requests come from Germany, the United States, and France. Notably, the United States ranks among the top users. According to Christoph Weissthanner, there are several reasons: “Some U.S. organizations deliberately store sensitive data outside American cloud environments for legal or compliance reasons. Additionally, risk diversification plays a role, as natural disasters in certain parts of the U.S. can threaten data center availability, prompting companies to seek alternatives.”

The growing demand for Nextcloud is not surprising. Transparency is becoming increasingly important. “We are transparent and open source. Everything is online, everything can be reviewed. If you don’t like it, you can fork the software—copy the code and adapt it to your needs. You can also extend it with apps while keeping Nextcloud as a base,” said Jos Poortvliet, Nextcloud co-founder.