Microsoft and LibreOffice have long been locked in a quiet, ongoing struggle for dominance in the world of office productivity software, but recent statements from the LibreOffice camp have thrust this rivalry—and its implications—back into the spotlight. At the heart of the issue lies the battle over document standards, with LibreOffice having publicly accused Microsoft of intentionally wielding “unnecessarily complex” file formats as a weapon to lock in users and stifle competition in the office suite market.
File formats are more than mere containers for words, numbers, and slides—they act as the DNA governing how content is presented, edited, and shared across platforms and programs. LibreOffice, which underpins many Linux distributions and serves as a vital free alternative, champions the OpenDocument Format (ODF), an international open standard designed from the ground up to be free from single-vendor control. Formats like .odt for documents and .ods for spreadsheets embody this principle. By contrast, Microsoft relies on its proprietary Office Open XML (OOXML), yielding the ubiquitous .docx and .xlsx files millions use each day.
Despite the different philosophies behind their creation, both file types utilize XML (Extensible Markup Language) for structure and data definition. With XML and its companion, the XML Schema Definition (XSD), the promise is theoretically simple: enable interoperability, so documents can seamlessly traverse across office suites and platforms. Yet, LibreOffice argues that Microsoft’s approach is anything but bridging.
A striking analogy from LibreOffice compares the file format landscape to a public railway system whose tracks are governed by a singular, intentionally complex control scheme. Although, in theory, any train should run on public tracks, the opaque and convoluted nature of Microsoft’s “railway control signals” turns the journey into an exclusive club—accessible only to those with the proprietary keys.
One practical example frequently cited is the deeply nested, sometimes seemingly arbitrary, tags within OOXML. While the end user sees a straightforward sentence in Word, that same sentence might become a labyrinth of nested XML tags and unpredictable attribute names when viewed “under the hood.” Many optional elements add further confusion, so any developer attempting to build a true alternative must reverse-engineer a standard with moving parts and unclear boundaries. The results are often imperfect, leading to formatting glitches, broken images, or missing elements when opening Office files in other suites—a reality familiar to anyone swapping documents between Word and LibreOffice Writer.
This echoes industry criticism that has dogged Microsoft since the early 2000s, when Office formats were entirely proprietary and undocumented. The 2008 standardization of OOXML as an ISO/IEC standard (29500) was meant to quell these concerns, but implementation details and adherence vary. Notably, Microsoft’s own application of OOXML often deviates from even the agreed-upon standard, further frustrating efforts at genuine interoperability.
A real-world comparison of ODF and OOXML files by software engineer Alex Brown, who served as a convenor during ISO standardization efforts, found that ODF documents are generally more readable and easier to parse by third-party tools. In contrast, OOXML often includes elements derived from legacy binary formats, further encumbered by “transitional” tags and undocumented behaviors that only Microsoft’s applications interpret correctly.
Moreover, attempts by open-source projects such as LibreOffice and Apache OpenOffice to provide comprehensive .docx compatibility continue to lag behind, not for want of technical talent but due to the tangled web of optional features and vendor-specific quirks embedded within OOXML. Even Google Docs, a resource-rich web app, sometimes falters when importing or exporting Microsoft’s formats—a testament to the challenge’s scale.
Official Microsoft documentation affirms that “OOXML schema represents the full breadth of document features in Office…including those required to ensure faithful round-tripping of content”. It’s a compelling argument for enterprise customers whose archives depend on these features. However, critics counter that cleaner alternatives are possible, pointing to ODF’s relatively consistent structure.
IT decision-makers thus face an implicit penalty for considering alternatives: migration projects take longer, cost more, and may result in user dissatisfaction when files don’t transfer smoothly. Even public sector bodies, often charged with promoting open standards, have struggled with this “soft lock-in.” Notably, the UK government’s Cabinet Office in 2014 made headlines when it attempted to standardize on ODF for government business, only to find that full compatibility with externally received .docx and .xlsx files proved unreachable in practice.
This reinforces the exact “lock-in logic” LibreOffice decries. As more organizations standardize their workflows around Microsoft 365, and as more legacy documents remain in OOXML formats, competitors are forced to devote scarce resources to imperfect compatibility layers rather than innovation or new features. The end result: users have less genuine choice.
In its appeal, LibreOffice encourages both Windows and Office users to consider making the leap to Linux and LibreOffice—a move it argues offers greater transparency, user freedom, and adherence to true open standards. The feasibility of such a switch, however, is an open question, particularly for large organizations with extensive Office-customized workflows or dependence on specific features.
The European Union, in particular, has advanced open formats as a pillar of its software procurement policies, though enforcement has, at times, been inconsistent. Industry bodies such as the Open Source Initiative and Free Software Foundation continue to lobby for stricter testing and conformance benchmarks, aiming to close the loopholes that allow ostensibly “standardized” formats to remain functionally exclusive.
Meanwhile, user advocacy groups stress the importance of digital literacy. As technical as the details of file formats may seem, the implications for users—lost access, high costs, reduced competition—are all too real. Encouraging users to demand open standards and agitate for regulatory oversight becomes part of a broader struggle to preserve user rights in the digital age.
If regulators, developers, and end users collectively insist on genuine interoperability, the market may shift. Until then, the silent but powerful force of technical complexity will continue to shape who controls tomorrow’s documents—and, by extension, the information and workflows that underpin modern life. The choice between openness and lock-in is not merely technical, but a defining decision about the values we bring to the digital age.
Source: Neowin LibreOffice calls out Microsoft for using "complex" file formats to lock in Office users
Decoding the Battle of Office File Formats
File formats are more than mere containers for words, numbers, and slides—they act as the DNA governing how content is presented, edited, and shared across platforms and programs. LibreOffice, which underpins many Linux distributions and serves as a vital free alternative, champions the OpenDocument Format (ODF), an international open standard designed from the ground up to be free from single-vendor control. Formats like .odt for documents and .ods for spreadsheets embody this principle. By contrast, Microsoft relies on its proprietary Office Open XML (OOXML), yielding the ubiquitous .docx and .xlsx files millions use each day.Despite the different philosophies behind their creation, both file types utilize XML (Extensible Markup Language) for structure and data definition. With XML and its companion, the XML Schema Definition (XSD), the promise is theoretically simple: enable interoperability, so documents can seamlessly traverse across office suites and platforms. Yet, LibreOffice argues that Microsoft’s approach is anything but bridging.
From Promise to Proprietary: The Reality of OOXML Complexity
LibreOffice’s latest, pointed critique is that Microsoft’s implementation of OOXML is “intentionally” overengineered to the point of exclusion. According to commentators from The Document Foundation (which stewards LibreOffice), the issue is not simply a matter of supporting advanced formatting or legacy features—as Microsoft often claims—but is a deliberate effort to make interoperating with .docx and .xlsx arduous or impossible for would-be competitors.A striking analogy from LibreOffice compares the file format landscape to a public railway system whose tracks are governed by a singular, intentionally complex control scheme. Although, in theory, any train should run on public tracks, the opaque and convoluted nature of Microsoft’s “railway control signals” turns the journey into an exclusive club—accessible only to those with the proprietary keys.
One practical example frequently cited is the deeply nested, sometimes seemingly arbitrary, tags within OOXML. While the end user sees a straightforward sentence in Word, that same sentence might become a labyrinth of nested XML tags and unpredictable attribute names when viewed “under the hood.” Many optional elements add further confusion, so any developer attempting to build a true alternative must reverse-engineer a standard with moving parts and unclear boundaries. The results are often imperfect, leading to formatting glitches, broken images, or missing elements when opening Office files in other suites—a reality familiar to anyone swapping documents between Word and LibreOffice Writer.
Motives Beneath Technical Complexity
Why would Microsoft maintain or exacerbate this complexity in the face of industry trends favoring interoperability and open standards? LibreOffice’s answer is direct: lock-in. By making OOXML implementation so daunting that few, if any, competitors achieve reliable compatibility, Microsoft ensures that users—individuals, businesses, and governments—stick with Office for fear of losing data fidelity or document appearance. Once a critical mass of content is “locked” in the Microsoft format, switching away becomes risky, administratively costly, or simply unappealing.This echoes industry criticism that has dogged Microsoft since the early 2000s, when Office formats were entirely proprietary and undocumented. The 2008 standardization of OOXML as an ISO/IEC standard (29500) was meant to quell these concerns, but implementation details and adherence vary. Notably, Microsoft’s own application of OOXML often deviates from even the agreed-upon standard, further frustrating efforts at genuine interoperability.
Is the Critique Justified? Weighing the Evidence
LibreOffice’s claims, while sharp, are not without foundation. Technical write-ups and developer forums abound with examples illustrating OOXML’s complexity. As open-source developer Mike Saunders—a prominent voice in the LibreOffice community—noted in his blog, “Even the simplest of paragraphs can result in a morass of XML, with a single sentence sometimes wrapped in a dozen or more tags, some of which bear little relevance to human editors or the content itself.” This isn’t just idle griping: multiple independent code audits and migration reports confirm similar headaches.A real-world comparison of ODF and OOXML files by software engineer Alex Brown, who served as a convenor during ISO standardization efforts, found that ODF documents are generally more readable and easier to parse by third-party tools. In contrast, OOXML often includes elements derived from legacy binary formats, further encumbered by “transitional” tags and undocumented behaviors that only Microsoft’s applications interpret correctly.
Moreover, attempts by open-source projects such as LibreOffice and Apache OpenOffice to provide comprehensive .docx compatibility continue to lag behind, not for want of technical talent but due to the tangled web of optional features and vendor-specific quirks embedded within OOXML. Even Google Docs, a resource-rich web app, sometimes falters when importing or exporting Microsoft’s formats—a testament to the challenge’s scale.
Microsoft’s Position: A Case for Backward Compatibility?
Microsoft has, on occasion, addressed these accusations by pointing to the need to support decades of legacy documents and customer workflows, some of which rely on obscure or rare formatting capabilities. The official line stresses that OOXML’s design is shaped by a commitment to backward compatibility—a necessity given the massive global installed base of Office products stretching back to the 1990s.Official Microsoft documentation affirms that “OOXML schema represents the full breadth of document features in Office…including those required to ensure faithful round-tripping of content”. It’s a compelling argument for enterprise customers whose archives depend on these features. However, critics counter that cleaner alternatives are possible, pointing to ODF’s relatively consistent structure.
The Business Case for Lock-In
Beyond the technical question lies a clear, arguably intentional, business logic. The more difficult it becomes for users to leave the Microsoft ecosystem without sacrificing fidelity, the stronger Microsoft’s market position. This logic extends beyond just Office itself; cloud-based solutions such as Microsoft 365 rely on seamless document handling as a value proposition, integrating Word, Excel, and PowerPoint files across collaborative workspaces.IT decision-makers thus face an implicit penalty for considering alternatives: migration projects take longer, cost more, and may result in user dissatisfaction when files don’t transfer smoothly. Even public sector bodies, often charged with promoting open standards, have struggled with this “soft lock-in.” Notably, the UK government’s Cabinet Office in 2014 made headlines when it attempted to standardize on ODF for government business, only to find that full compatibility with externally received .docx and .xlsx files proved unreachable in practice.
Cloud, Collaboration, and the Next Stage of Fragmentation
While file format complexity is a longstanding issue, it takes on fresh importance in a world pivoting towards cloud-based collaboration. Microsoft 365’s online editing tools and real-time co-authoring depend on seamless use of OOXML files. Google Workspace, meanwhile, has reversed its strategy, increasingly accommodating .docx files directly rather than forcing conversion to its native format. This pragmatism reflects one market reality: the dominance of Microsoft’s formats is so entrenched that resistance can often amount to self-harm.This reinforces the exact “lock-in logic” LibreOffice decries. As more organizations standardize their workflows around Microsoft 365, and as more legacy documents remain in OOXML formats, competitors are forced to devote scarce resources to imperfect compatibility layers rather than innovation or new features. The end result: users have less genuine choice.
Windows 11, Interoperability, and The Push for Alternatives
LibreOffice’s critique does not stop at file formats; it also connects Microsoft’s “complexity” strategy to broader platform pressures, notably Microsoft’s relentless push to migrate the user base to Windows 11. According to The Document Foundation, features justified as “security improvements” or “performance gains” are often rolled out as mandatory requirements that lack compelling technical underpinnings—serving instead as means of keeping users within the Microsoft ecosystem for both operating systems and applications.In its appeal, LibreOffice encourages both Windows and Office users to consider making the leap to Linux and LibreOffice—a move it argues offers greater transparency, user freedom, and adherence to true open standards. The feasibility of such a switch, however, is an open question, particularly for large organizations with extensive Office-customized workflows or dependence on specific features.
The Road Ahead: Regulation, Standards, and User Advocacy
Amid renewed scrutiny, calls for regulatory action have once again begun to grow. Proponents of open source and digital sovereignty argue that governments and enterprises have a responsibility to mandate the use of true open standards—formats and protocols fully and transparently documented, with no vendor-specific extensions or ambiguities.The European Union, in particular, has advanced open formats as a pillar of its software procurement policies, though enforcement has, at times, been inconsistent. Industry bodies such as the Open Source Initiative and Free Software Foundation continue to lobby for stricter testing and conformance benchmarks, aiming to close the loopholes that allow ostensibly “standardized” formats to remain functionally exclusive.
Meanwhile, user advocacy groups stress the importance of digital literacy. As technical as the details of file formats may seem, the implications for users—lost access, high costs, reduced competition—are all too real. Encouraging users to demand open standards and agitate for regulatory oversight becomes part of a broader struggle to preserve user rights in the digital age.
Strengths, Weaknesses, and What’s at Stake
The ongoing clash between Microsoft and LibreOffice is ultimately about much more than technology; it encompasses issues of user autonomy, innovation, market dynamics, and even the health of democratic governance, where long-term access to public records must not be hostage to proprietary formats.Notable Strengths:
- Interoperability and User Choice: Open standards like ODF encourage true competition and empower users to switch tools without data loss.
- Transparency: Open file specifications allow for public scrutiny, broader adoption, and innovation by open-source and commercial projects alike.
- Long-Term Access: For governments and archives, open formats ensure future generations can read today’s documents without proprietary dependencies.
Potential Risks and Weaknesses:
- Compatibility Penalties: In reality, imperfect support for OOXML limits the real-world viability of alternatives, frustrating users and raising costs.
- Complex Migration: Moving away from entrenched Microsoft formats requires careful planning and technical resources, deterring many organizations.
- Slow Adoption: Despite advocacy, the dominance of .docx and .xlsx remains overwhelming in business, academia, and governments.
Conclusion: Beyond Lock-In, Towards True Digital Freedom?
LibreOffice’s fiery critique of Microsoft’s file format strategy highlights crucial questions about the direction of the digital world. As our dependence on office documents grows, the need for open, maintainable, and accessible standards is not mere idealism—it’s foundational to competition, innovation, and user sovereignty. While Microsoft’s defenders can point to legitimate legacy requirements and feature support that justify OOXML’s design choices, the persistence of practical lock-in undercuts the promises of open digitization.If regulators, developers, and end users collectively insist on genuine interoperability, the market may shift. Until then, the silent but powerful force of technical complexity will continue to shape who controls tomorrow’s documents—and, by extension, the information and workflows that underpin modern life. The choice between openness and lock-in is not merely technical, but a defining decision about the values we bring to the digital age.
Source: Neowin LibreOffice calls out Microsoft for using "complex" file formats to lock in Office users
