Windows 11 update Breaking Localhost Connections: A Deep Dive & Solutions
Recent Windows updates are causing widespread issues with connections to localhost (127.0.0.1), impacting developers, IT professionals, and everyday users alike. Numerous reports are surfacing indicating a failure to establish HTTP connections to locally hosted web servers. This disruption affects critical applications relying on this functionality, including debugging tools, security software, and authentication systems.
WhatS Happening?
Following the rollout of Windows 11 updates 24H2 and 25H2, many users are finding that applications requiring interaction with services running on thier own machines are failing. Specifically, the October KB5066835 update and the September KB5065789 preview update appear to be the root cause.
This issue isn’t limited to a single application. Visual Studio debugging, SQL Server Management Studio (SSMS) Entra ID authentication, and the Duo Desktop app – which verifies device security – are all experiencing connectivity problems.
Impact on Duo Users
Duo, a popular multi-factor authentication provider, has acknowledged the problem. Their support bulletin details how the update can prevent successful authentication when using features like trusted Endpoints,Duo Desktop & Device Health policies,and Verified Duo Push with Bluetooth.Essentially,if your security relies on verifying your device’s health through a local connection,you may encounter login issues.
Potential Fixes – What You Can Try
Several potential solutions have been proposed by the community, but results vary.Here’s a breakdown of what’s being discussed:
* Registry Edit: Some users suggest disabling HTTP/2 protocol via a registry modification. While reported as effective by some, this fix hasn’t been independently verified. to attempt this, you can modify these entries:
“`
[HKEY_LOCAL_MACHINESystemCurrentControlSetServicesHTTPParameters]
“EnableHttp2Tls”=dword:00000000
“EnableHttp2Cleartext”=dword:00000000
“`
* Microsoft Defender Update: Installing the latest Microsoft Defender intelligence update has been suggested, but reports indicate it doesn’t consistently resolve the issue.
* Uninstall Problematic Updates (Recommended): The most reliable solution currently is to uninstall the problematic Windows updates. This restores functionality for most affected users.
How to Uninstall the Updates
You can remove the updates using the following commands in an elevated command Prompt (run as administrator):
wusa /uninstall /kb:5066835wusa /uninstall /kb:5065789
After uninstalling these updates, a system restart is required to fully apply the changes and restore localhost connectivity.
What to Expect moving Forward
The situation is evolving. We’ve reached out to Microsoft for comment and will provide updates as soon as we receive a response. In the meantime, uninstalling the updates remains the most effective workaround.
this issue highlights the importance of testing updates in a non-production environment before widespread deployment. It also underscores the potential for unforeseen consequences when core system components are modified. We will continue to monitor the situation and provide updates as they become available.
