1. Check if You’re Affected
- Try opening a localhost/IIS site or any app that uses loopback (e.g., Visual Studio debugging, SSMS, Duo Desktop).
- If you see errors like ERR_CONNECTION_RESET or ERR_HTTP2_PROTOCOL_ERROR, you’re impacted.
2. Immediate Workarounds
Option A: Uninstall the Problematic Update
Run in Command Prompt (Admin):
wusa /uninstall /kb:5066835 wusa /uninstall /kb:5065789
- Restart your machine after uninstall.
- This restores localhost/IIS functionality but removes October security fixes.
Option B: Disable HTTP/2 (Temporary Fix)
- Open Registry Editor (
regedit).
- Navigate to:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\HTTP\Parameters
- Add a new DWORD (32-bit) Value:
- Name:
EnableHttp2
- Value:
0
- Restart your machine.
This forces Windows to use HTTP/1.1, bypassing the broken HTTP/2 stack.
3. Permanent Fix (Preferred for Enterprises)
Apply Microsoft’s Known Issue Rollback (KIR)
- Download the KIR Group Policy MSI for your Windows version (24H2, 25H2, or Server 2025) from Microsoft’s official site.
- Install the MSI on your domain controller.
- Open Group Policy Editorand navigate to:
Computer Configuration → Administrative Templates → <KIR Policy Name>
- Enable the rollback policy.
- Run
gpupdate /force on affected clients or wait for policy refresh.
4. Other Issues & Fixes
| Issue | Fix |
|---|
| DRM-protected content fails |
Wait for Microsoft patch; use modern streaming apps |
| SMB v1 file sharing broken |
Switch to SMB v2/v3 (SMB v1 is deprecated) |
| WUSA installer errors |
Use Windows Update or WSUS instead |
5. Recommended Action Plan
- Developers / Local IIS users → Use HTTP/2 registry fix or uninstall update immediately.
- Enterprise IT → Deploy KIR via Group Policy for scale.
- Security-conscious environments → Prefer KIR over uninstalling updates, since it keeps security patches intact.
If you already get the issue, in order to make sure you get latest update please make sure you switch get the latest update in Windows Update