The Microsoft Windows 10 discontinuation lawsuit is an individual complaint filed by California resident Lawrence Klein in San Diego County Superior Court on August 7, 2025, asking a judge to order Microsoft to keep providing free Windows 10 security updates until the operating system falls below 10 percent of all Windows devices. Klein argues Microsoft ended support prematurely to force consumers into buying new AI-capable PCs running Windows 11.1Courthouse News Service. Microsoft Sued for Discontinuing Windows 10 Support2San Diego Superior Court. Case Detail: 25CU041477C
Who Filed the Lawsuit
Klein owns two laptops that run Windows 10 but cannot be upgraded to Windows 11 because they lack a TPM 2.0 chip.3The Register. California Man Sues Microsoft Over Windows 11 Upgrades The case, numbered 25CU041477C, was filed as an individual action rather than a class action. His law firm, CounselOne, has said publicly that it is investigating potential class claims and is soliciting contact from other affected consumers.4AZ Capitol Times. Lawsuit Seeks to Stop Microsoft From Ending Windows 10 Support
What the Lawsuit Claims
The complaint brings four California causes of action: the Unfair Competition Law (Business and Professions Code § 17200), the False Advertising Law (§ 17500), the Consumers Legal Remedies Act (Civil Code § 1750), and a count for declaratory and injunctive relief. It also invokes the federal Sherman Act and Clayton Act, along with California’s Cartwright Act.5Courthouse News Service. Klein v. Microsoft Complaint
The theory tying those statutes together is that Microsoft is using its dominance in desktop operating systems to corner the generative AI market. Windows 11 ships with the Copilot chatbot, and the complaint alleges Copilot runs best on new “Copilot+ PCs” equipped with a neural processing unit. By cutting off Windows 10 security updates while roughly 240 million PCs cannot meet Windows 11’s hardware requirements, the complaint argues, Microsoft is herding users into buying new AI-ready machines.1Courthouse News Service. Microsoft Sued for Discontinuing Windows 10 Support6Tom’s Hardware. California Man Sues Microsoft for Discontinuing Windows 10
The complaint also alleges Microsoft and its hardware partners failed to tell buyers at the point of sale how long their operating system would be supported or what would happen when support ended. Klein notes the four-year window between the launch of Windows 11 and the end of Windows 10 support is roughly half the span Microsoft gave users during previous transitions.7FindLaw. It’s a Digital David Versus Goliath as Man Sues Microsoft Over Ending of Windows 10 Support Beyond consumer harm, the complaint raises cybersecurity exposure for users left on an unsupported system and the electronic waste that would result from scrapping hundreds of millions of working PCs.1Courthouse News Service. Microsoft Sued for Discontinuing Windows 10 Support
What the Lawsuit Asks the Court to Do
Klein is not seeking damages for himself. The complaint asks for public injunctive relief with two main components. First, an order requiring Microsoft to keep providing free Windows 10 security updates until the operating system’s share of Windows devices drops below 10 percent. Second, an order requiring Microsoft and its hardware partners to disclose at the point of purchase how long the operating system will be supported, whether the device can run the next version, and what happens at end of support.
As a fallback, the suit asks the court to force Microsoft to relax Windows 11’s hardware requirements, particularly the TPM 2.0 rule, so existing Windows 10 computers can upgrade.3The Register. California Man Sues Microsoft Over Windows 11 Upgrades The only money sought is attorneys’ fees.1Courthouse News Service. Microsoft Sued for Discontinuing Windows 10 Support
Why the End-of-Support Date Matters
Microsoft ended support for Windows 10 on October 14, 2025, meaning no more security updates, software patches, or technical support. The operating system still runs, but Microsoft warns that unpatched devices face greater exposure to viruses and malware.8Microsoft. Windows 10 Support Has Ended Windows 11 requires a TPM 2.0 chip and only officially supports a limited list of processors, so many functioning PCs cannot upgrade.9Microsoft. Windows 11 on Devices That Don’t Meet Minimum System Requirements
Windows 10 was still running on about 42 percent of Windows desktops worldwide in late October 2025 and more than 26 percent in May 2026, which is part of why the complaint’s 10 percent threshold has practical bite.10Computerworld. Windows 10’s Market Share Is More Than Hanging in There Despite Being at End of Support11StatCounter. Windows Version Market Share Worldwide
Microsoft does offer a paid Extended Security Updates program. In the United States, consumers can get one more year of security-only updates (through October 2026) for $30, or free by syncing PC settings to the cloud or redeeming 1,000 Microsoft Rewards points.12Microsoft. Windows 10 Extended Security Updates Businesses start at $61 per device in year one, with the price doubling each year for up to three years.13Microsoft. Extended Security Updates for Windows 10 The consumer program covers security fixes only, with no technical support or feature updates.
Weaknesses in the Case
Legal commentators have pointed to several hurdles. Microsoft provided a decade of free security updates for Windows 10, and a court would have to decide whether that qualifies as an unreasonably short lifespan. The paid ESU program, whatever its limits, offers a documented upgrade path. And free alternative operating systems such as Linux and ChromeOS can run on hardware that Windows 11 rejects, which weakens the claim that users have been stranded.7FindLaw. It’s a Digital David Versus Goliath as Man Sues Microsoft Over Ending of Windows 10 Support The antitrust theory connecting an operating system sunset to monopolization of the generative AI market is novel and has not been tested in court.
Where the Case Stands
As of mid-2026, the case is still in its early stages in San Diego Superior Court.14PC Mag. Microsoft Sued for Killing Windows 10, Lawsuit Says It’s Forcing AI Upgrades Microsoft did not respond to media requests when the complaint was filed, and in September 2025 a spokesperson told ZDNet the company had “nothing to share at this time.”15ZDNet. Consumer Reports Slams Microsoft for Windows 10 Mess, Urges Extension of Free Updates No amended complaint, class certification motion, or substantive ruling has been reported publicly.
Concessions Microsoft Has Already Made Elsewhere
The lawsuit asks a California court to do something Microsoft has partly done voluntarily in other markets, which shapes what counts as a realistic outcome.
In Europe, the consumer group Euroconsumers challenged Microsoft’s approach under the EU’s Digital Markets Act, arguing that charging for security updates or conditioning them on cloud syncing violated the rules for gatekeeper platforms.16Help Net Security. Windows 10 Extended Security Updates Europe17Windows Central. Major Backtrack as Microsoft Makes Windows 10 Extended Security Updates Free for an Extra Year18Thurrott. Microsoft Accepts to Make Windows 10 Extended Security Updates Free for EU Consumers That concession does not reach users in the United States.
Microsoft has also carved out education. K–12 and higher education institutions can buy Extended Security Updates for $1 per device in year one, $2 in year two, and $4 in year three, far below the business rate.19PIRG. Why Microsoft Extended Windows 10 Support for Schools By 2025, Microsoft had extended free security updates to U.S. schools through 2027.20KQED. Repair Advocates Tell Microsoft: Stop the End of Windows 10