We are experiencing internet performance issues across multiple systems after installing Windows update KB5089549 on Windows 11 version 25H2.

Hi Surya Prakash,

Based on your description, the slowdown appears tied to changes introduced by the update rather than your network infrastructure. Some cumulative updates can affect network stack components, including NIC drivers or TCP/IP optimizations. Even after uninstalling the update, residual configuration changes may persist, which explains why intermittent slowness continues.

The first step I recommend is to confirm that all affected systems have the latest NIC drivers from the hardware vendor, not just the default Windows drivers. Next, check whether the update modified advanced adapter settings such as offloading, RSS, or MTU size. Resetting these to defaults often restores performance. Running “netsh int ip reset” and “netsh winsock reset” can also clear any lingering stack changes.

If the issue persists, you may want to temporarily pause updates on production systems until Microsoft releases a servicing fix. In parallel, monitor the Windows Update Health Dashboard for advisories related to KB5089549, as Microsoft typically publishes known issues and workarounds there.

For enterprise environments, another best practice is to validate cumulative updates in a pilot group before broad deployment. This helps catch regressions like the one you’re experiencing.

I hope this explanation helps clarify the situation. If this answer is helpful, please don’t forget to hit “Accept Answer”.

Jason.

No internet performance or connectivity issues related to Windows 11, version 25H2 or to KB5089549 are described in the provided context. The context only lists other known and resolved issues (for example, HTTP.sys/IIS connection resets, Direct Access reconnection issues, app hangs when saving to cloud storage, Microsoft account sign-in failures, specific KB install failures, and app-specific problems), and none match organization-wide slow internet performance after KB5089549.

Because of this, no KB-specific workaround or fix for KB5089549 can be provided from the context. The only supported guidance in similar Windows update issues in the context is:

1. Ensure the latest cumulative/security updates are installed when Microsoft has released a fix for a known issue.
2. If an update is suspected of causing issues and uninstalling it does not fully resolve the problem, perform an in-place repair/reinstall of Windows 11 using installation media, as was done to resolve repeated update failures and post-update app corruption in similar cases.
3. If the problem persists across multiple systems and is not covered by documented known issues, open a support case with Microsoft so the issue can be investigated and, if needed, addressed in a future update.

References:

• Resolved issues in Windows 11, version 25H2
• Resolved issues in Windows 11, version 24H2
• November 8, 2022—KB5019980 (OS Build 22621.819)
• November 8, 2022—KB5019961 (OS Build 22000.1219)
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