96% Duopoly Squeezes Euro-Office Into Microsoft’s Web

96% is the number that should haunt every argument about Euro-Office 1.0: Microsoft 365 and Google Workspace dominate online office software, and Europe’s new open-source challenger will fail if it wins compatibility but loses control.

Euro-Office reached its first stable release on June 9, according to ZDNet, backed by a coalition that includes Nextcloud, Ionos, and other Euro-Stack participants. The pitch is direct: a browser-based, open-source office suite that European organizations can host on EU infrastructure under EU law.

My view: Euro-Office is a necessary challenge to Microsoft 365 and Google Workspace, but it weakens its own sovereignty case if Microsoft document formats sit at the center of the product. Compatibility gets users through the door. Defaults decide who owns the room.

1.0 arrives, but the product is still more component than suite

Euro-Office 1.0 is not a drop-in desktop replacement for Microsoft Office. Its own backers describe it more narrowly:

"Euro-Office is more of an integration component. It merely handles document editing itself. Storage, as well as navigation, permissions, and sharing logic, have to be offered by a platform it is integrated in, like Proton Docs, Nextcloud Hub, or OpenProject."

That matters. Euro-Office depends on surrounding platforms for the parts users often experience as “the office suite”: file storage, sharing, permissions, and workflow. Packaged options already exist, including Nextcloud Hub 26 Spring, Ionos' Nextcloud Workspace, and Office.eu, but the first deployments are web-based rather than standalone desktop suites.

ZDNet’s hands-on assessment was blunt: usable, but rough. The core editor works. Real-time collaboration works. Configuration is “fiddly.” The frontend still carries OnlyOffice branding in places, and the release looks closer to a tech preview than a production-ready platform for cautious institutions.

That shouldn’t be disqualifying. Version 1.0 rarely carries the burden of a continent’s digital policy. But Euro-Office chose a big slogan, and big slogans invite harder scrutiny.

Microsoft formats remain the practical language of office work

The uncomfortable truth is that DOCX, XLSX, and PPTX are still the formats most organizations encounter every day. The source material puts it plainly: “Microsoft Office formats are what most people use every day.”

That gives Euro-Office a real product problem. A rival to Microsoft 365 cannot ask users to accept broken tables, mangled presentations, unreliable tracked changes, or document round-tripping that collapses under daily work. If files don’t survive exchange with clients, regulators, partners, schools, and agencies, the migration dies in procurement before ideology gets a vote.

So yes, high-fidelity Microsoft format support is not optional. It is the admission ticket.

But that’s exactly why defaults matter. The default file format decides which standard gets normalized, which vendor behavior everyone else must chase, and which document logic becomes the baseline for future work. If Euro-Office defaults to Microsoft’s OOXML formats, it may help users leave Microsoft’s apps while keeping Microsoft’s format gravity intact.

XOOMAR analysis: this is the same control question running through other parts of tech. Who defines the operating layer? We’ve tracked that tension in AI tooling too, including SkillOpt Bets AI Agents Can Improve Without Retraining and 1,000 Tokens a Second: DiffusionGemma Breaks LLM Math. The office-suite version is older, quieter, and arguably more embedded in public administration.

Euro-Office can’t sell sovereignty with Microsoft-shaped defaults

Euro-Office is being framed as “a solution for editing documents, spreadsheets, and presentations, developed as a true sovereign community collaboration of over a dozen different organizations.”

That phrase sets the bar. Sovereignty cannot mean only European hosting, European governance, and open-source code. Those are important. They are not enough.

Open-source productivity also depends on transparent standards, long-term document accessibility, and freedom from a dominant vendor’s roadmap. If a public agency switches away from Microsoft 365 but keeps creating, saving, and archiving documents in Microsoft-centered formats by default, it has reduced one dependency while preserving another.

Here’s the clean split:

The right product answer is not to ignore Microsoft formats. That would be fantasy. The right answer is to treat them as import and export channels, not the native center of a European sovereign office stack.

LibreOffice backers picked the right fight, even if the timing is messy

The Document Foundation, steward of LibreOffice, has become Euro-Office’s loudest critic. Its June 7 open letter challenged Euro-Office’s marketing claim of being “the first European open-source office suite,” pointing instead to OpenOffice.org and LibreOffice, both rooted in Europe’s office software history.

That branding fight is secondary. The stronger argument is about file formats.

TDF objects to Euro-Office defaulting to Microsoft’s OOXML rather than Open Document Format, or ODF. Its sharpest line deserves the attention it has received:

"Compatibility is not sovereignty,"

TDF also argued that a European-branded suite saving every file in OOXML “is de facto an ally of Microsoft in its content lock-in strategy.”

That is harsh. It is also directionally right. The argument is not that Euro-Office should refuse to read or write Microsoft files. The argument is that a sovereign suite should not make Microsoft’s format logic its default storage logic.

LibreOffice has spent years pushing ODF as a real alternative. Its frustration with a new open-source cloud suite chasing Microsoft compatibility is predictable. More than that, it is useful. Euro-Office needs pressure from the standards side before its defaults harden into institutional habit.

The best defense of Euro-Office is also the trap

Euro-Office supporters have the strongest counterargument: users won’t switch if documents break.

They are right. European public-sector migrations cannot succeed without strong Microsoft document handling. Any cloud-based Microsoft 365 alternative must meet users where their files already live. Otherwise, it becomes a purity project with nice principles and no adoption.

Euro-Office also has a governance argument. It is built as a fork of OnlyOffice’s open-source core. Its supporters frame that fork as necessary to align development, hosting, and legal jurisdiction with European public-sector requirements. They cite concerns about OnlyOffice’s strategic decisions, transparency, and geopolitical ties with Russia. The licensing dispute with Ascensio System SIA was reportedly resolved in time for launch, and Bradley Kuhn, co-author of the GNU AGPLv3, agreed with the Euro-Office developers’ licensing stance.

That defense matters. Control over development and jurisdiction is real sovereignty work.

But compatibility can be a bridge. The problem begins when the bridge becomes the destination.

Open defaults should be product policy, not activist decoration

Euro-Office should make ODF the default for new documents, collaboration, storage, and archiving, while keeping Microsoft formats as high-quality import and export options. That is the only position consistent with its stated mission.

This does not require punishing users. It requires product discipline.

Euro-Office should make format choices visible. It should invest in conversion quality. It should give administrators clear controls over defaults. It should help procurement teams distinguish “runs on European infrastructure” from “stores public-sector knowledge in open formats.”

The project’s own supporters say ODF support is on the roadmap and that “Ultimately, ODF should be the standard - not OOXM, and we will work towards that,” according to a Euro-Office spokesperson quoted by The Register in the supplied material. Good. Now make that roadmap concrete enough for governments, schools, and companies to evaluate before they migrate.

A sovereign cloud office suite cannot rely on vibes. It needs defaults that express its politics in code.

The next test is whether Euro-Office normalizes freedom or familiarity

Euro-Office should publicly commit to open-by-default document handling and prove that browser-based collaboration can work without Microsoft formats as the center of gravity.

Governments, schools, and companies evaluating it should ask three questions before celebrating the launch:

• Defaults: What format does a new document use automatically?
• Archives: Can documents remain accessible without Microsoft’s behavior as the reference point?
• Governance: Who controls the standard that future users will inherit?

Euro-Office 1.0 is welcome. The open-source office market needs more serious cloud contenders, not fewer. But if Europe wants digital sovereignty, it can’t stop at European servers and familiar ribbons.

A true Microsoft 365 rival has to compete on control. Otherwise, it is just another office suite living inside Microsoft’s document logic.

Impact Analysis

• Euro-Office targets Europe’s reliance on dominant U.S. productivity platforms.
• Its dependence on Microsoft document formats could undermine its sovereignty argument.
• Early deployments may appeal to EU organizations, but the product still appears more like an integration component than a full suite.