⚠️ 3 verified solutions available for Error 14021 — Last updated 2026-04-04
Error 14021 📋

Fix ERROR_SXS_DUPLICATE_DLL_NAME — Windows Error Code 14021

Error 14021 (ERROR_SXS_DUPLICATE_DLL_NAME) is a Windows Internet & WinHTTP error that occurs when two or more components referenced directly or indirectly by the application manifest have files by the same name.. This guide provides step-by-step solutions to resolve this issue.

🏷️ Code: 14021 📛 ERROR_SXS_DUPLICATE_DLL_NAME 📅 Updated: 2026-04-04 ⏱️ 3 Solutions
⚡ Quick Fix

Re-register the DLL File: Open Command Prompt as Administrator

👇 See all 3 solutions below
🐞 Auto-Fix Script for Error 14021
⚠️ How to use: Open PowerShell as Administrator, paste the code above, and press Enter.
✓ Safe & Transparent ✓ No Downloads Required ✓ Review Before Running
📑 Table of Contents
What is Error 14021? Common Causes Step-by-Step Solutions Prevention Tips Related Errors

💡 What is Error 14021?

Windows System Error Code 14021, known as ERROR_SXS_DUPLICATE_DLL_NAME, is a Internet & WinHTTP error that occurs during WinHTTP, WinInet, and internet protocols. The error indicates that: Two or more components referenced directly or indirectly by the application manifest have files by the same name. When this error is encountered, the Windows operating system was unable to complete the requested operation within the internet services subsystem. The error code 14021 is returned by the GetLastError() function and provides developers with a specific identifier to diagnose the root cause of the failure. The symbolic name ERROR_SXS_DUPLICATE_DLL_NAME maps directly to this numeric code and is commonly referenced in Microsoft documentation, developer forums, and system logs. Understanding this error and its context within WinHTTP, WinInet, and internet protocols is essential for effective troubleshooting.

⚠️ Common Causes

  • A required Visual C++ Redistributable package is not installed
  • The DLL was deleted by aggressive antivirus software
  • An application uninstaller accidentally removed a shared DLL
  • The DLL version is incompatible with the running application
📚 Comprehensive Guide

Troubleshooting COM and DCOM Architectural Failures (Event ID 10016)

A comprehensive guide on Component Object Model (COM), Distributed COM (DCOM), and how to safely interpret and resolve Event ID 10016 errors.

Read the full guide →

✅ Step-by-Step Solutions

1 Re-register the DLL File
  1. Open Command Prompt as Administrator
  2. Run: regsvr32 filename.dll (replace filename.dll with the missing DLL)
  3. If it says 'the module failed to load', the DLL file itself is missing
  4. In that case, run: sfc /scannow to restore system DLLs
  5. For non-system DLLs, reinstall the application that provides the file
Advertisement
[AdSense In-Article Ad Generator]
Show Advanced Solutions (2 more)
2 Install the Required Redistributable
  1. Most missing DLLs come from Microsoft Visual C++ Redistributable or DirectX
  2. Download Visual C++ 2015-2022: https://aka.ms/vs/17/release/vc_redist.x64.exe
  3. Download DirectX: https://www.microsoft.com/en-us/download/details.aspx?id=35
  4. Install both, restart your computer, and retry
3 Copy DLL from Another Windows Installation
  1. ONLY do this for system DLLs, and ONLY from the same Windows version
  2. Find the DLL in C:\Windows\System32 on a working PC with the same Windows version
  3. Copy it to your System32 folder (you may need to take ownership first)
  4. Run: regsvr32 filename.dll to register it
  5. WARNING: Never download DLLs from third-party websites — they may contain malware

🎬 Video Tutorials

▶️ Watch Video Tutorials
How to fix Error 14021 (Sxs Duplicate Dll Name)
Open on YouTube →

💻 Diagnostic Command

Run this PowerShell command to find related events in your system log:

Get-EventLog -LogName System -Newest 20 | Where-Object {$_.Message -like "*14021*" -or $_.Message -like "*ERROR_SXS_DUPLICATE_DLL_NAME*"} | Format-List

💡 Open PowerShell as Administrator, paste the command above, and press Enter.

🛡️ Prevention Tips

  • Install all Visual C++ Redistributable packages (2005 through 2022)
  • Add game/application folders to your antivirus exclusion list
  • NEVER download individual DLL files from the internet — always install the parent package
Was this helpful?
Last updated: 2026-04-04
📖
Based on Official Microsoft Documentation
Solutions Tested on Windows 10 & 11
Error codes sourced from Microsoft Win32 SDK. Updated 2026-04-04.
🔧 Diagnose Your Error