This document explains how to fix Microsoft Windows error C8000266 if it is not working properly or throwing an error while installing, updating or upgrading Windows.

The error message may look like:
– Windows could not search for new updates. An error occurred while checking for new updates for your computer.
– Some updates were not installed. Failed: 86 updates
Error(s) found: Code C8000266 Windows update encountered an unknown error.

This solutions applies for following version of Microsoft Windows:

  • Windows 7
  • Windows 8
  • Windows 8.1
  • Windows 10
Error C8000266 Windows Update Overview
Avg. Time to Resolve Issue   50 mins
Difficulty Hard
Log Name: MicrosofWindowsUpdateError1842.log
Source: Service Control manager
Event ID: 7236
Operating System
  • Windows 7
  • Windows 8
  • Windows 8.1
  • Windows 10
Level: System Error
User: System
  • Faulting Application Name: Window Update Manager , version: 4.8.3156.20845, time stamp: 0×83504719
  • Faulting module name: Windows  log.dll, version: 3.7.5352.01329
  • Exception code: 0xd04g231b
  • Fault offset: 0xd09b968a
  • Faulting process ID: 0×442
  • Faulting application start time: 0x800g1b41487906
  • Faulting application path: ~<userpath>
  • Faulting module path: ~C:\Windows\System32
  • Report ID: f9e39e41-2276-87e1-8513-2385bab2f129
Also Known as
  • WindowsUpdate_c8000266
  • C8000266
  • WindowsUpdate_C8000266e
  • C8000266e
  • 0xC8000266
  • fehler code C8000266, foutcode C8000266, fejlkode C8000266, code d’erreur C8000266, codice di errore C8000266, feil kode C8000266, cod de eroare C8000266, código de error C8000266

Cause of C8000266 Windows Update Error Code

  • Incompatible Internet proxy configuration
  • Microsoft Windows internal Application Conflict

Steps to resolve Windows Error C8000266

Step 1: Check if your network is behind Proxy

1. Press down Windows Key + R and Type “CMD” (without quotes)
2. Hit Enter key
Office Resolve Error Proxy Check 3. In command Prompt Copy following commands (Simply select the command and press ctrl+c and press ctrl+v in command prompt)

 netsh winhttp import proxy source=ie 

Check Proxy Setting

Note: You will need Administrator Access to Run the above command. Simply Right Click on CMD button and select “Run as Administrator

If you get the message “Direct Access (no proxy server)“, continue to the next step otherwise disable proxy from Network Settings.

 You can contact our 24×7 Live support for any help during the whole process. 

Step 2: Temporarily Disable any installed 3rd Party Antivirus

Some times Antivirus/Malware/Adware programs mark Microsoft Windows installer files as Spam and block it from installing. Please refer your vendors website for disabling it temporarily. Once installation is done you can activate it again.

In most cases Microsoft Windows update error code C8000266 should be resolved by following above steps. If however the issue still persists it means there is some critical issue with your system which needs to be fixed manually and is recommended to be done by an experienced Computer Technician.

You can chat one-on-one with one of our Microsoft Certified Support Representative 24/7 by clicking on the Chat button.

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Last Updated: 24/01/2016
Solution ID: 524275

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    April 13th, 2016

    Posted In: Microsoft Windows

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