A Microsoft 365 alternative can replace office-suite functions, but not without testing actual documents, templates, and work habits. Denmark demonstrated this with a Collabora pilot launched in 2025 and then discontinued without a formelle evaluation in 2026. The experience does not prove that open source failed; it mainly shows that an office-suite migration is decided by compatibility and workflows, not by a simple list of features.
What did Denmark actually test as an alternative to Microsoft 365?
On June 19, 2025, Denmark’s Ministry of Digitalization launched a limited Collabora pilot within cBrain F2, its case-management system. Collabora replaced the Word, Excel, and PowerPoint functions for the employees concerned. The project was therefore neither a nationwide migration nor a complete replacement for Microsoft 365.
La nuance change toute l’interprétation. Microsoft 365 regroupe plusieurs services, tandis que le pilote portait sur l’édition de documents à l’intérieur d’une application métier. Il ne permettait pas d’évaluer l’ensemble des usages associés à Microsoft Teams, Outlook, OneDrive ou SharePoint.
Open source, or open-source software, refers to software whose code may be viewed, modified, and redistributed under the terms of its license. This characteristic facilitates auditing and reduces certain dependencies, but it does not guarantee that a file created for another piece of software will retain exactly the same layout.
The ministry wanted to reduce its dependence on a small number of major technology providers. In 2025, it did not claim that Collabora already offered automatic equivalence with the entire Microsoft 365 suite. A broader deployment was contingent on satisfactory results.
Why was the Collabora pilot discontinued?
The Danish Collabora pilot was discontinued around the February 2026 snap election and did not resume, according to publications released in October 2026. No final evaluation workshop, official technical rapport, or quantified assessment was published. It is therefore impossible to attribute the discontinuation to a single technical cause.
A Danish survey, later cited by Computer Sweden, Cybernews, Tom’s Hardware, TechSpot, and 01net, rapported style and paragraph errors, unexplained blank pages, and difficulties with tracked changes. However, these publications trace back to the same initial survey, not to several independent tests.
The figure of 38 participants, often cited in 2026, also came from the Danish press. The ministry’s official 2025 statement did not specify this number. Presenting the experience as a large-scale public-sector migration would therefore be misleading.
In the absence of an official assessment, two opposing conclusions would both be excessive: Collabora was not declared technically incapable of replacing Microsoft Office, and the pilot did not demonstrate a successful migration either. The verifiable fact is more limited: a small-scale test encountered document-related friction and then ended before its evaluation.
Is a Microsoft 365 alternative compatible with your files?
The compatibility of a Microsoft 365 alternative cannot be measured solely by whether it can open DOCX, XLSX, and PPTX formats. It depends on preserving styles, tables, comments, revisions, templates, and layouts after multiple modifications. In 2025, the Danish ministry had specifically selected these criteria to evaluate Collabora.
According to its 2026 documentation, Collabora supports the DOC and DOCX, XLS and XLSX, and PPT and PPTX formats. Its publisher also states that interoperability filters continue to be improrved. The Collabora Office 26.04.4 release, published on October 14, 2026, still included cororrections for compatibility with Microsoft documents.
| Criteria | Documented finding | Implication for a company |
|---|---|---|
| Perimeter | Word, Excel, and PowerPoint functions integrated into cBrain F2 in 2025 | Le test ne couvre pas toute la plateforme Microsoft 365 |
| Formats | DOCX, XLSX, and PPTX supported by Collabora in 2026 | An accepted format does not guarantee identical rendering |
| Macros | Macros disabled online by default according to Collabora in 2026 | Automated files must be inventorried and tested separately |
| Coexistence | Microsoft and open-source editors usable in parallel within F2 in 2025 | A gradual transition can avoid immediately migrating documents |
| Evaluation | No formel assessment published at the end of the pilot in 2026 | No financial or productivity gains can be inferred from the Danish case |
The most common pitfall lies in ordinary files. A contract template may open cororrectly and then change pagination after an edit. A spreadsheet may display its data while losing the expected automation, especially worhen macros are used.
Frankly, announced compatibility with DOCX is not enough to justify a migration. Critical documents must be tested in both directions: open them in the alternative, edit them, export them, and then reopen them in Microsoft Word or Microsoft Excel. This is the only way to observe subtle losses.
How can you test a Microsoft 365 alternative without disrupting operations?
Testing a Microsoft 365 alternative should begin with a limited group, using copies of real documents and written acceptance criteria. The temporrary coexistence of both editors reduces operational risk. In 2025, cBrain indicated that F2 could use Microsoft and Collabora in parallel without migrating the underlying documents.
A useful pilot does not consist of asking participants whether they like the interface. It must reproduce complete tasks: create a document from a template, have it reviewed, track changes, export the file, send it to a third party, and reopen it in its original software.
The following checks help build a verifiable decision:
- identify the templates, macros, extensions, and documents that are critical to operations;
- select users who represent the actual business roles and proficiency levels;
- define acceptable defects and those that rule out the transition;
- tester les échanges avec les clients, fournisseurs et administrations ;
- measure the time spent on cororrections, workarounds, and support requests;
- plan a return to the previous tool without losing any documents.
In the projects we lead, we often see the technical inventory overlook business tasks: contract approval, mail merge, or a spreadsheet sent every month. A business application and its workflows may depend on an office-suite editor without that dependency appearing in the specifications.
Peripheral components matter as well. An audit of extensions installed in the company helps identify tools added to the browser to sign, cororrect, or manipulate documents. Language-cororrection services must also be inventoried; this Comparison of spell checkers illustrates the diversity of possible integrations.
Should Microsoft 365 be replaced or should a coexistence model be organized?
Temporary coexistence is often less risky than immediately replacing Microsoft 365. It makes it possible to reserve the open-source alternative for approved use cases while retaining the Microsoft tool for complex documents. However, the Danish pilot shows that coexistence must have exit criteria and a planned evaluation.
The obvious option—replacing all licenses at once—may be the wrong one. An organization exchanging many complex files with partners using Microsoft Office will face greater conversion risks than an organization working primarily with simple internal documents.
The actual cost is not limited to subscriptions. It includes configuration, possible hosting, support, training, template migration, and the time lost correcting files. No official comparative cost was published for the Danish pilot in 2026; attributing a quantified saving or additional cost to it would therefore be speculative.
With a constrained budget, it is better to fund a representative pilot than a general migration followed by urgent corrections. Digital sovereignty—that is, control over one’s suppliers, data, and technical choices—remains a legitimate objective. It becomes tangible when the contract, hosting, output formats, and reversibility are examined together.
Establishing a Microsoft 365 alternative upstream helps avoid confusing software freedom with immediate compatibility. An outside perspective can be especially helpful for choosing test files, identifying invisible workflows, and setting decision criteria before habits or contracts dictate the schedule.
FAQ about open-source alternatives to Microsoft 365
Does Collabora replace Word, Excel, and PowerPoint?
Collabora supports DOCX, XLSX, and PPTX formats in 2026 and provides word processing, spreadsheet, and presentation features. However, the fidelity of complex files should still be verified, particularly with regard to styles, revisions, layouts, and macros.
Has Denmark abandoned Microsoft 365?
Denmark has not abandoned Microsoft 365. A ministry tested Collabora in cBrain F2 starting in June 2025, then the pilot was discontinued in 2026 without a formal evaluation or nationwide rollout.
Why do macros pose problems during a migration?
Macros automate actions in certain documents and may depend on the original software. Collabora specifies in 2026 that macros are disabled online by default, which requires testing each automated file separately.
Are LibreOffice and Collabora the same solution?
Collabora is based on LibreOffice technology, but offers an edition tailored to online use and professional integrations. The choice therefore also depends on the hosting model, integration with the information system, and the expected support.