European Commission officials have preliminarily determined that Amazon Web Services (AWS) and Microsoft Azure should be designated as digital “gatekeepers” under the bloc’s Digital Markets Act (DMA), a move that could force the tech giants to open up their cloud platforms and reshape how Windows integrates with online services. The June 25, 2026, notification marks the first time the EU has targeted cloud infrastructure providers under the landmark regulation, adding a new chapter to Brussels’ years-long campaign to level the digital playing field.

Both AWS and Azure now have the opportunity to rebut the preliminary findings before a final decision is issued later this year. If the designations stick, the companies would be required to comply with a strict set of interoperability, data portability, and self-preferencing rules specific to their cloud businesses, potentially affecting everything from Windows’ built-in cloud features to how enterprises manage multi-cloud architectures. Neither Microsoft nor Amazon commented publicly on the preliminary finding, but both are expected to mount vigorous appeals, industry sources say.

What the DMA means for cloud gatekeepers

The Digital Markets Act, which came fully into force in 2023, defines gatekeepers as large online platforms that provide an important gateway between business users and end users. Until now, the EU has focused primarily on consumer-facing services—designating companies like Alphabet, Meta, and Apple in areas such as search, social media, and operating systems. Microsoft’s Windows operating system was itself designated under the DMA in 2024, forcing changes such as the unbundling of Teams from Windows 11 in the European Economic Area.

Now, the European Commission has turned its attention to the cloud. In a statement, the Commission said its preliminary investigation found that AWS and Azure each hold a “significant impact on the internal market, provide a core platform service that is an important gateway for business users, and enjoy an entrenched and durable position.” The thresholds for automatic designation under the DMA—a market capitalization of more than €75 billion and over 45 million monthly active end users in the EU—are easily met by both companies, but the Commission can also initiate a qualitative assessment. In this case, officials looked at the cloud market structure, switching costs, and the deep integration of these cloud platforms with other enterprise tools.

Crucially, the preliminary ruling targets only the cloud infrastructure services of AWS and Azure, not the entire Amazon or Microsoft empire. However, because Azure is so tightly woven into Microsoft’s ecosystem—including Windows, Microsoft 365, and Dynamics—the compliance burdens could have a dramatic ripple effect on how Windows handles data, authentication, and default services.

The Windows connection: deep integration under scrutiny

For years, Microsoft has steered Windows users toward Azure-based services. OneDrive, Microsoft’s cloud storage platform, is built on Azure and deeply embedded in File Explorer. Windows 11’s “recommended” section in the Start menu often promotes OneDrive backups, and the default save location in many configurations points to OneDrive. Meanwhile, Azure Active Directory (now Entra ID) powers the sign-in experience for Windows 10 and 11 devices joined to corporate domains, creating a seamless but hard-to-disentangle bond between the OS and Microsoft’s cloud.

Under the DMA, self-preferencing is explicitly prohibited. That means Microsoft could be forced to give third-party cloud storage providers equal footing in Windows’ user interface. For example, the operating system might have to offer users a clear choice during setup to pick a default cloud provider—similar to how the browser ballot screen worked in Europe a decade ago. Dropbox, Google Drive, or independent EU cloud services could demand that their apps be integrated as seamlessly as OneDrive is today.

“This isn’t just about letting users uninstall OneDrive,” said a Brussels-based competition lawyer who spoke on condition of anonymity. “It’s about the dozens of APIs, the single sign-on flows, and the backup routines that are all tied to Azure. Microsoft might have to document those interfaces and provide third parties with the same level of access—or rip them out entirely for European customers.”

Azure’s “entrenched position” and enterprise lock-in

The Commission’s preliminary findings point to specific practices that may stifle competition. One concern is technical lock-in through proprietary services such as Azure SQL Database, Cosmos DB, and AI tools like Azure OpenAI Service. These offerings are tightly integrated with Azure’s identity and networking layers, making it costly and complex for businesses to move workloads to other clouds. While not unique to Azure—AWS has similar hooks with its AI and database services—Microsoft’s ability to bundle these with Windows Server licenses and hybrid benefits gives it an extra edge in the enterprise market.

If Azure is designated as a gatekeeper, the DMA would compel Microsoft to allow business users to port their data to alternative providers free of charge and without technical barriers. It could also force Azure to make its APIs and tools interoperable with rivals’ platforms. For Windows-centric businesses, that might mean a future where Active Directory easily federates with Google Cloud or where Windows admin consoles can provision resources on AWS directly.

“Many of our clients use Windows Server on-premises and are slowly moving to Azure because it’s the path of least resistance,” said an IT consultant who works with mid-sized European manufacturers. “If Microsoft has to open up the APIs, it might actually accelerate multi-cloud strategies because the integration tax disappears.”

Amazon’s AWS in the crosshairs

While much of the Windows-specific impact centers on Microsoft, the designation of AWS as a gatekeeper carries its own significance. AWS is the global market leader in cloud infrastructure, and its dominance in the EU is even more pronounced. The preliminary finding notes that Amazon uses its cloud position to favor its own services, such as Amazon Connect and SageMaker, over third-party alternatives on the AWS Marketplace. The DMA would force AWS to treat all marketplace vendors equally and might require it to separate certain bundled offerings.

For Windows users and administrators, the AWS designation is less directly felt on the desktop, but it could reshape the broader cloud landscape. If AWS must lower its data transfer fees or make it easier to export virtual machine images, enterprises running Windows Server on AWS could find it cheaper to diversify their cloud spending. That, in turn, could weaken the gravitational pull that Azure currently exerts on Windows shops.

Parallels to past EU tech battles

The EU’s move echoes its earlier interventions against Microsoft. In 2004, Brussels forced Microsoft to offer a version of Windows without Windows Media Player and to share server protocols with competitors. In 2009, a browser choice screen was imposed. Those remedies were seen as modest successes that nudged the market toward more openness. But the DMA is far more sweeping: it allows the Commission to impose proactive, self-executing obligations without the need for years of litigation.

“The difference now is speed and scale,” said a legal scholar who studies EU tech regulation. “The Commission can designate a gatekeeper, define the specific obligations, and start fining companies up to 10% of their global annual turnover within months. Microsoft and Amazon won’t have the luxury of dragging their feet through Luxembourg courts for a decade.”

Already, industry groups representing European cloud providers have cheered the preliminary findings. CISPE, a trade group that includes smaller European cloud companies, said in a statement that “this is the first step toward unlocking the grip that hyperscalers have on the market.” Yet some large enterprise customers are wary. “We’ve built our entire identity infrastructure on Azure AD. If Microsoft is forced to disassemble that, we could end up paying for a costly migration,” said the CIO of a German financial services firm.

What happens next

Microsoft and Amazon now have until August 2026 to respond to the Commission’s preliminary findings. A final decision on designation is expected by October 2026. If the designations are confirmed, the companies would then have six months to come into compliance with most DMA obligations, though some technical mandates could have a longer phase-in period.

For Microsoft, compliance will almost certainly involve changes to Windows. The company might need to release a “cloud choice” update for Windows 11 and Windows 10, likely as part of a mandatory security patch. That update could introduce a new settings page where users pick their preferred cloud storage provider and enterprise authentication method. Insiders say Microsoft is already exploring such a feature internally, code-named “Project Horizon,” though the company has not publicly acknowledged it.

Amazon, for its part, may need to overhaul its AWS Marketplace to give equal visibility to independent software vendors and might have to publish APIs that let customers more easily replicate their entire cloud environment on competing infrastructure. AWS CEO Matt Garman said earlier this year that the company was “committed to customer choice,” but he stopped short of endorsing forced interoperability.

The bottom line for Windows users

For the average Windows user in the EU, the immediate effects might be subtle: a new setup prompt, a different default cloud icon in File Explorer, or smoother integration with alternative storage services. But over the long term, these changes could fundamentally reshape the Windows experience. Microsoft’s strategy of stitching its own services into the fabric of the operating system may no longer be viable if regulators demand equal treatment for competitors.

Businesses that depend on Windows and Azure will need to start auditing their dependencies now. If the DMA forces Microsoft to offer truly portable data and open APIs, some organizations may seize the chance to reduce their reliance on a single vendor. Others may be forced to re-architect their applications if deep Azure-specific features are spun off or modified.

One thing is certain: after years of battling over browsers and media players, the new frontier of EU tech regulation is the cloud—and it’s coming for the heart of Microsoft’s ecosystem.