🔧 Introducing Windows Update Error 0x80073701 – Missing Files? Let’s Fix It Like a Pro

Encountering Error 0x80073701 during a Windows Update is a common frustration. This error essentially means the update failed because required system files couldn’t be found or are corrupted. It’s not just a random glitch; it signals issues with Windows’ Side-by-Side (SxS) assembly system. In this comprehensive guide, we’ll walk you through every solution clearly and thoroughly, so you can confidently tackle the issue and restore your system like a troubleshooting expert.

1. What Does Error 0x80073701 Mean?

Error 0x80073701 links back to the “Side-by-Side” (SxS) mechanism in Windows. It indicates that the update installer couldn’t locate certain necessary components or DLLs, likely because they are missing or corrupted.

2. Step‑by‑Step Fixes: Try These in Order

2.1 🔄 Step 1: Restart Your PC

Sometimes updates fail due to temporary glitches. A simple restart can clear locked files, release pending services, and allow Windows to complete the update smoothly.

How to:

1. Click Start → Power → Restart.
2. After reboot, check for updates again via Settings → Update & Security.

2.2 🛠 Step 2: Use DISM and SFC to Repair System Files

If core system components are corrupt, you’ll need to repair them using built-in tools.

Procedure (run as an administrator):

1. Right-click the Start button → choose Windows Terminal (Admin).
2. Run:

2. This command checks and repairs Windows image corruption.
3. Once complete, run:

3. This scans all protected system files and replaces any incorrect versions.
4. After both commands complete, restart your PC and try Windows Update again. Repeat these commands if needed.

Why it works:

• DISM uses Windows Update or a WIM file to heal component store issues.
• SFC ensures core .dlls and system files match Microsoft’s official versions.

2.3 🧰 Step 3: Run the Windows Update Troubleshooter

Windows has built-in diagnostics for update issues.

Steps:

1. Go to Start → Settings → System → Troubleshoot → Other troubleshooters.
2. Locate Windows Update and click Run.
3. The tool will detect and fix common update problems, or give error messages that guide your next actions.

2.4 📥 Step 4: Manually Download & Install the Update

If automatic updating fails, manual installation via the Microsoft Update Catalog can bypass installer issues.

How to manually install:

1. Note the KB number of the failed update (e.g. KB5006670).
2. Visit the Microsoft Update Catalog website.
3. Search for the KB, download the correct package (x64 vs x86), then run the installer.
4. Reboot and confirm the update succeeded.

2.5 📂 Step 5: Inspect the CBS Log (Advanced)

The CBS log (C:\Windows\Logs\CBS\CBS.log) holds detailed info about missing or damaged components.

Recommended for advanced users:

• Open in a text editor and look for error lines like ERROR_SXS_ASSEMBLY_MISSING.
• Copy relevant sections and seek help in the Microsoft Community, Reddit, or tech forums.
• Alternatively, you can use the log to manually replace or register missing DLLs.

2.6 🔧 Step 6: In‑Place Upgrade (Repair Install)

When all else fails, an in-place upgrade (or repair-install) reinstalls Windows without touching your applications or personal files.

Repair-install steps:

1. Download the Media Creation Tool from Microsoft.
2. Run it, choose “Upgrade this PC now”, and follow the on-screen prompts.
3. Your system is reinstalled while preserving your data and programs—though backing up beforehand is still wise.

3. When Is This Error Most Common?

This error often occurs with major Windows releases or cumulative updates, especially after changes introduced in late 2024. Factors include outdated drivers or security software conflicting with the update process.

It’s most frequent:

• Immediately after a fresh install
• During big version upgrades
• When incompatible third‑party software is running

🧩 Advanced Tips & Pro-Level Insights

🔍 Tip 1: “Failed” Update May Actually Be Installed

Sometimes, even if Windows Update shows a failure, the update might still be successfully applied in the background.

How to tell:

• The update is no longer being offered repeatedly.
• CBS.log or WindowsUpdate.log doesn’t show critical unresolved errors.

In such cases, you can safely ignore the failure message. (Or, it may be more accurate to say that the issue has resolved itself despite the reported failure.)

🧠 Tip 2: Use CheckSUR Tool (for Windows 7/8)

If you’re working on older systems like Windows 7 or 8, try using the System Update Readiness Tool (CheckSUR) provided by Microsoft.

This tool can fix deep SxS (Side-by-Side) component issues that often trigger error 0x80073701.

Microsoft Support Page – KB947821

🧨 Pro Trick 1: Manually Reset Windows Modules Installer

This error can occur when too many updates are stuck in a “pending” state. You can manually reset the TrustedInstaller service:

⚠️ Warning: Only delete pending.xml if you are an experienced user. Always create a backup first to avoid irreversible changes.

💡 Pro Trick 2: Clean Up the WinSxS Component Store

Use this DISM command to clean up old update remnants and reduce component store corruption:

This command helps eliminate conflicts and dependency mismatches within the WinSxS folder.

✋ Tip 3: Try a Local Account Instead of a Microsoft Account

Some users have reported that switching from a Microsoft account to a local user account has allowed updates to complete successfully.

This workaround can be helpful when account-level permissions or synchronization issues are involved.

4. Tailored Solutions by Root Cause

You can run DISM and SFC repeatedly if needed. Even if updates still show “failed” in your update history, the system’s functionality may already be restored,meaning that a single reported failure can often be safely ignored.

📝 FAQs

Even if the system seems stable, failing to address this error could leave your device vulnerable to security threats or lead to further update issues down the road.

The in-place upgrade process is user-friendly and doesn’t require technical expertise. As long as you follow the on-screen steps and ensure your data is backed up, it’s one of the safest repair methods available

🧠 Final Takeaway

Error 0x80073701 can be unsettling, but in most cases, it can be resolved step by step. Start with reboots and built-in tools, then move on to manual installations, and only use a repair install as a last resort. Staying up-to-date ensures both performance and security, making it well worth the time to fix this properly.

Let me know if you hit a snag at any step—I’m here to help.

✔️For more troubleshooting guides,check out:

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タグ: Repair Install, Windows 11, Windows 10, DISM, SFC, 0x80073701, Windows Update Error, Update failed, Windows troubleshooting, CBS.log