Windows 11 has finally crossed the majority threshold. In July 2025, the operating system captured 52% of desktop web traffic, according to Statcounter, overtaking Windows 10 for the first time since its launch almost four years ago. The milestone, a 15-percentage-point surge in six months, arrives just three months before Microsoft is set to end normal support for Windows 10 on October 14, 2025. Yet the same data reveals that 44.59% of Windows PCs are still running the aging OS, translating to hundreds of millions of active devices.

That lingering installed base is now at the center of a contentious California lawsuit that accuses Microsoft of designing the Windows 10 sunset to force hardware upgrades and lock users into its AI ecosystem. Plaintiff Lawrence Klein filed the complaint in San Diego Superior Court seeking a court order compelling Microsoft to keep issuing free Windows 10 security updates until the operating system’s share drops to 10% of Windows devices. The case, which names Microsoft’s Copilot+ and Windows 11 hardware requirements as instruments of a deliberate obsolescence strategy, is the most direct legal challenge yet to the company’s lifecycle policies.

The Lawsuit’s Core Allegations

Klein’s filing, widely reported in tech media, contends that Microsoft intentionally timed the Windows 10 end-of-support to drive consumers toward Windows 11-capable PCs and, by extension, Copilot+-branded hardware that integrates generative AI features. The complaint highlights the TPM 2.0 mandate, Secure Boot, and supported CPU lists as technical barriers that render many otherwise functional machines ineligible for the free in-place upgrade. Klein owns two laptops that cannot meet those requirements, leaving them without a no-cost path to continued security patching.

The legal action frames the Extended Security Updates (ESU) program — Microsoft’s first consumer-facing paid support extension — as coercive. To enroll, consumers must either sync device settings to a Microsoft Account, redeem 1,000 Microsoft Rewards points, or pay a one-time fee widely reported at $30. The complaint alleges these conditions disproportionately burden privacy-conscious users, low-income households, and small businesses. It also seizes on a widely cited analyst projection from Canalys that as many as 240 million PCs could become e-waste due to Windows 11 incompatibility, arguing Microsoft’s policy will cause environmental harm.

The requested injunction is extraordinary: a court would force Microsoft to fund and deliver free Windows 10 security patches indefinitely, until the operating system’s active user base shrinks to a plaintiff-defined threshold. No monetary damages are sought; Klein asks only for declaratory relief and attorney’s fees.

Market Reality: Millions Still Stuck on Windows 10

Statcounter’s July 2025 data provides concrete context. When Windows 11 stood at 36.65% in January, the migration pace looked lethargic; the subsequent surge — adding over 15 percentage points in six months — suggests the looming deadline is finally motivating upgrades. Yet almost 45% of Windows devices remain on Windows 10, a share that would equate to roughly 600 million PCs globally if total Windows active devices are around 1.4 billion. Even after accounting for the acceleration, a massive cohort will not have transitioned by October 14.

Microsoft has long telegraphed the retirement date. Mainstream support for Windows 10 was originally scheduled to end in 2020 for some editions before being extended, and the final End of Life date was published years in advance. The company now points users toward three options: upgrade eligible devices to Windows 11, purchase a new Copilot+ PC, or enroll in the ESU program. The consumer ESU, announced earlier in 2024 and detailed in a support document, provides critical updates through October 13, 2026. Enrollment paths include the free Rewards or backup-sync routes, but the requirement to link a Microsoft Account has drawn criticism.

Hardware Requirements as a Friction Point

The most controversial element is the minimum system specification for Windows 11. Microsoft’s official requirement for TPM 2.0, a hardware security module present on most PCs manufactured after mid-2016, is the primary cutoff. Many systems built before that date lack the chip, and while enthusiast workarounds exist, they are unsupported and may break with future updates. The company frames TPM 2.0 as essential for modern security features such as virtualization-based security and Windows Hello biometrics, but critics argue that the security benefit does not justify rendering millions of PCs obsolete.

The Canalys e-waste estimate, while an analyst projection rather than a definitive count, has been repeatedly cited by the plaintiff and environmental advocates. The figure assumes that the affected PCs will lose value to refurbishers and be discarded, contributing to a global e-waste crisis. Microsoft has not publicly challenged the estimate, but it has highlighted sustainability initiatives elsewhere in its business.

The ESU Program: A Bridge or a Barrier?

The Windows 10 Consumer ESU program is new territory for Microsoft, which has historically offered extended support only to enterprise volume-licensing customers. For $30, a single Microsoft Account can cover multiple devices, as recently confirmed by the company. The free redemption paths lower the financial barrier, but the mandatory account linkage has led privacy advocates to argue that the program exchanges a user’s data for security updates. Critics also note that the one-year extension merely delays, rather than solves, the underlying incompatibility.

Organizations face steeper costs: $61 per device for the first year, doubling for subsequent years, with a maximum of three years. IT administrators can enroll through the Microsoft Volume Licensing Program. This pricing structure incentivizes hardware refreshes for businesses, which is exactly the dynamic Klein’s lawsuit claims is anticompetitive.

Legal observers are skeptical that Klein can secure the unprecedented relief he seeks. Courts traditionally defer to companies’ product lifecycle decisions unless a clear statutory violation exists. The plaintiff must demonstrate irreparable harm, likelihood of success on the merits, and that an injunction would serve the public interest. Microsoft will argue that it gave ample notice, provided mitigation options, and that TPM 2.0 is a defensible security measure.

The complaint reportedly advances claims under California’s Unfair Competition Law, Consumers Legal Remedies Act, and False Advertising Law. These consumer-protection statutes require proving deceptive or unfair conduct, and Microsoft can point to its publicly documented lifecycle calendar and support articles as evidence of transparency. The anticompetitive framing — that the lifecycle policy furthers Microsoft’s market position in generative AI — adds complexity; establishing a causal link between OS retirement and AI market foreclosure would demand substantial discovery and expert testimony.

Procedurally, a preliminary injunction could be sought on an expedited basis, but a final ruling, including appeals, is unlikely before October 14. Even if a California court granted some relief, Microsoft’s global legal resources all but guarantee a protracted fight. Any decision would also be limited to the jurisdiction, meaning the immediate practical impact on worldwide users would be limited.

What Happens If the Court Sides with Klein?

A judicial order requiring free Windows 10 updates past October 14 would upend Microsoft’s engineering and financial planning. The company would need to reallocate security response and maintenance teams to a codebase it intended to sunset, incurring ongoing costs. The precedent could ripple across the tech industry, inviting similar challenges to other end-of-life announcements and prompting regulators to scrutinize hardware-software coupling more closely.

For consumers, a court victory could delay the forced upgrade timeline, but it would not resolve the underlying hardware gap. A mandated extension might slow the Windows 11 transition, creating a bifurcated ecosystem where Microsoft must support two major OS versions for years. This could fragment security postures and delay the adoption of modern platform features that Microsoft argues are necessary to defend against advanced threats.

Practical Steps for Users and IT Teams

While the litigation unfolds, the October 14 deadline remains fixed. The following steps can help individuals and organizations prepare:

  • Inventory and assess: Catalog all Windows 10 devices, checking for TPM 2.0, CPU compatibility, and RAM. Microsoft’s PC Health Check tool automates this.
  • Evaluate ESU: For ineligible but critical systems, the consumer or organizational ESU provides a one- to three-year bridge. Understand the enrollment prerequisites, including the Microsoft Account requirement for consumer plans.
  • Test upgrades: For eligible hardware, pilot the Windows 11 upgrade in a controlled environment to surface application and driver issues before a broad rollout.
  • Consider alternatives: Linux distributions can extend the life of older hardware for non-specialized use cases. For mission-critical or regulated systems, plan hardware refreshes with compliance validation.
  • Harden legacy systems: Any device staying on Windows 10 without ESU should be isolated from sensitive networks, fortified with endpoint protection, and monitored for vulnerabilities.

The Broader Implications

Klein v. Microsoft transcends a single product retirement. It crystallizes growing tension between the technology industry’s relentless innovation cycles and the societal push for digital sustainability. The Canalys e-waste projection, whether precisely accurate or not, has refocused attention on the environmental cost of forced obsolescence. Meanwhile, regulators in Europe and the United States are already examining how dominant platforms leverage their ecosystems to advantage new product categories — Microsoft’s Copilot push is a case in point.

If the lawsuit gains traction, it could embolden consumer and environmental groups to challenge other hardware-software lock-ins. Even if it fails, the public conversation it has engendered may pressure Microsoft and its peers to extend support timelines, reduce artificial compatibility barriers, or invest more heavily in refurbishment and recycling programs. The case also tests the limits of consumer-protection law when applied to software licensing models that courts have historically treated as commercial decisions.

Microsoft’s market position is simultaneously stronger and more exposed than ever. Windows 11 now commands the majority of desktop usage, a sign that the upgrade strategy is working at scale. Yet the 44% holdouts represent a massive constituency that feels left behind, and their grievances are now being litigated in a court of law. How this case resolves — or whether it settles — will shape the narrative around product lifespans for years to come.