Document Foundation accuses Microsoft of hindering compatibility with complex file formats

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Ícones dos aplicativos do Office/Microsoft 365 - imagem: divulgação/Microsoft

Ícones dos aplicativos do Office/Microsoft 365 - imagem: divulgação/Microsoft

The entity responsible for maintaining and developing the most used free productivity suite in the world issued a firm position on the difficulties of interacting with the software from the Redmond giant. The central point of contention involves the architecture of the files generated by the programs Word, Excel and PowerPoint, whose DOCX, XLSX and PPTX extensions present layers of complexity that, according to the organization, intentionally harm competition.

Maintaining visual and functional fidelity when opening documents created in the proprietary environment has become a herculean task for developers of alternative solutions. The most recent version of LibreOffice, released in early 2026, brought several improvements specifically focused on translating these files, but the foundation claims that the effort required is disproportionate due to the technical barriers imposed.

This is not a request for funding or direct support, but rather a structural critique of the way standards are documented and applied. The organization maintains that, although the format is theoretically open, practical implementation favors the ecosystem of the creator of Windows, creating a scenario where full interoperability becomes practically unattainable for third parties.

Technical specifications and data volume

The standard known as Office Open XML (OOXML) serves as the backbone for modern office documents, but its structure is constantly questioned by experts in the free software industry. The criticism falls on the excessive density of the technical specifications that govern this format, transforming reading and writing files into a monumental technical challenge.

To illustrate the size of the obstacle, the official documentation that explains how these formats work exceeds seven thousand pages. Esse Massive volume of rules and exceptions forces independent development teams to dedicate thousands of hours just to decipher how a text or spreadsheet should be displayed, diverting resources that could be used for innovation.

The complexity does not seem to be accidental, according to the vision of the entity that manages LibreOffice, functioning as a market defense mechanism. The need to interpret so many variables creates a significant barrier to entry, discouraging new competitors and consolidating the dominance of tools that already have leadership in the corporate and domestic sector.

Divergences in international standards

A crucial technical aspect raised in the debate refers to adherence to international standards of standardization. Embora there is an ISO/IEC 29500 certification that defines how the format should work, the accusation is that market-leading products do not follow the “Strict” version of the standard, opting for a variant known as “Transitional”.

This transitional version allows the use of legacy elements and obsolete features that have been retained to ensure compatibility with very old versions of the proprietary software. The result is a hybrid and confusing code that mixes modern standards with outdated specifications, making life difficult for any other program trying to process the file in a clean and efficient way.

By perpetuating the use of this variant, a digital dialect is created that only the original applications can speak fluently. Isso generates formatting errors when the user tries to migrate to open platforms, giving the false impression that free software is inferior, when, in fact, he is trying to interpret an inconsistent standard.

Impact on free software development

The operational cost of maintaining compatibility with these proprietary formats drains valuable resources from the open source community. Engenheiros of software needs to constantly reverse engineer to understand undocumented behavior or non-standard implementations, rather than focusing on creating new functionality for users.

  • Developers spend time fixing layout breaks caused by unclear specifications.
  • Financial and human resources are diverted from innovation to maintaining compatibility.
  • The end user’s freedom of choice is limited by the fear of losing document formatting.
  • The cycle of dependence on a single supplier is artificially reinforced.

This dynamic results in a market with less real competition and greater difficulty in adopting open technologies in governments and companies. The foundation argues that true technological freedom will only exist when document standards are transparent, concise and independent of any specific vendor, allowing information to flow without technical tolls.

Historically, the battle over document standards reflects opposing views on the future of technology: on the one hand, the protection of closed ecosystems that guarantee recurring profits; on the other, the search for universal formats that guarantee the perpetuity and accessibility of digital information in the long term, regardless of the software used to access it.