Yes, a Windows 11 update killed “localhost” support — Microsoft breaks Windows again

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Okay, so Microsoft rolled out a Windows 11 update – KB5066835 – on October 14th, 2025, and honestly, it was a bit of a disaster. They meant to just push out some security and stability improvements, but it totally messed up localhost for a lot of us. As a developer, I can tell you, that’s a huge problem because I, like many others, use local testing *constantly*. It really threw a wrench into things.

TechPowerUp reported that a recent update caused problems with “localhost” connections – the standard way to test websites, apps, and APIs on your own computer. After the update, web browsers couldn’t access anything running locally, and local projects became unresponsive.

Localhost is a special address that lets your computer talk to itself. Developers use it to test websites and apps on their own machines before making them available online. Many popular development tools, such as Visual Studio, MySQL, PostgreSQL, and Docker, rely on localhost to function.

Regular internet users won’t notice any changes, but this is a significant issue for developers. That’s because ‘localhost’ is essential for their coding, debugging, and testing processes.

The problem was found to be with HTTP.sys, a core part of Windows that manages web connections. A recent update altered how it handles connections from the same computer, causing some local connections to either fail or disconnect unexpectedly.

Microsoft has fixed a recent problem, but some people actually found a solution themselves before the official fix was released. The issue was related to ‘localhost’ not working, and users were able to restore it by removing the KB5066835 update. If you also had the September preview update (KB5065789) installed, you might need to remove that one too. However, some people are still experiencing the problem, so the fix isn’t universal yet.

There’s a catch: getting rid of the update also means losing important security improvements. Users will have to choose between waiting for an official solution or removing the update to keep things running.

Another Windows update headache, and a familiar pattern is forming

It’s become increasingly common for Windows updates to cause problems, and issues with things like accessing your own computer (localhost) aren’t unusual. Lately, these updates have been particularly disruptive for advanced users, software developers, and IT professionals. It’s possible we’re just more aware of these problems now, as people’s opinion of Microsoft has declined. Still, it often feels like Windows is becoming less stable with each update.

A recent update to Windows caused problems with the system recovery process, preventing users from using USB keyboards and mice. Microsoft quickly released a fix to address this issue and ensure people could regain access to their computers.

A recent update unexpectedly caused problems with the Windows Media Creation Tool, which many people use to install or fix Windows. This happened right before support for Windows 10 ended.

Microsoft officially stopped supporting Windows 10 on October 14, 2025, meaning Windows 11 is now the only operating system they offer. This comes at a difficult time, as many users are already unhappy and recent issues suggest potential problems ahead for Windows.

There’s been a lot of negativity surrounding Microsoft recently, particularly regarding Windows and Xbox. Regardless of the cause, Microsoft CEO Satya Nadella claims that AI now helps write about 30% of their code. If that’s accurate, it’s crucial that human engineers still carefully review and test this code before it’s released to users.

Microsoft needs to restore trust in Windows updates

This is a symptom of a larger issue: people are losing trust in Windows updates. Increasingly, users are putting off installing updates because they worry it will cause problems, which contradicts Microsoft’s recommendations for staying secure. When users actively avoid updates, it indicates a serious problem.

This issue is a serious problem for developers, as using ‘localhost’ is essential to their daily work. Standard security updates shouldn’t disrupt this fundamental process. Now that Windows 10 is no longer supported, Windows 11 needs to be reliable and predictable, particularly if Microsoft wants developers to continue building on its platform.

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2025-10-22 17:12