Windows 11 Update Is Bricking Modems And It's A Feature, Not A Bug

The controversy around the Windows 11 January 2026 Update won't stop rolling in—and now, Microsoft is intentionally disabling support for legacy hardware, not simply breaking it on accident. Specifically, in the January 13th KB5074109 update, four essential dial-up modem drivers were removed. These driver files included agrsm64.sys, agrsm.sys, smseri64.sys, and smserial.sys. As Microsoft states flatly, "Modem hardware dependent on these specific drivers will no longer work in Windows,” and the only way for users to continue using modems reliant on those drivers with Windows 11 is to uninstall the update.

While there may be some understandable security concerns about long-term support for legacy hardware, this change isn't just impacting users in poor or underserviced areas forced to rely on home dial-up Internet services. A number of businesses and existing phone systems relied on these drivers, and new hardware reliant on these drivers is still coming to market. For whatever reason, Microsoft didn't even think to warn manufacturers before sending out this update rendering their hardware obsolete—Microsoft just did it and buried a "will no longer work" in some patch notes. For a premium product like Windows, that's questionable practice—particularly for enterprise users who were relying on some form of dial-up driver support for legacy systems to remain functional.


From the consumer perspective, this update breaking dial-up modem support is unlikely to have a large-scale effect and thus may wind up being overlooked. But for business users, rural users, and low-income users who are being impacted by this, it's yet another entry on an ever-growing list of reasons to move away from Windows 11. Microsoft surprise-mandating networking hardware upgrades and breaking workflows for users with an innocuous-looking security update is a big deal.

While the vulnerabilities within these legacy drivers are noted, it still feels like Microsoft should have tried to warn manufacturers and impacted users ahead of time, or provided an option to accept the patch without the driver file removal. As-is, another quiet killing of a legacy feature by Microsoft (like when it recently disabled a decades-old activation method), as spotted by the folks at Windows Central, isn't a great look, and impacted users are being left in a remarkably bad position.