⚠️ 3 verified solutions available for Error 4404 — Last updated 2026-03-18
Error 4404 📋

Fix ERROR_APP_DATA_REBOOT_REQUIRED — Windows Error Code 4404

Error 4404 (ERROR_APP_DATA_REBOOT_REQUIRED) is a Windows DNS & WINS error that occurs when fast cache has been rearmed and requires a reboot until it can be updated.. This guide provides step-by-step solutions to resolve this issue.

🏷️ Code: 4404 📛 ERROR_APP_DATA_REBOOT_REQUIRED 📅 Updated: 2026-03-18 ⏱️ 3 Solutions
⚡ Quick Fix

Reset Windows Update Components: Open Command Prompt as Administrator

👇 See all 3 solutions below
🐞 Auto-Fix Script for Error 4404
⚠️ 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 4404? Common Causes Step-by-Step Solutions Prevention Tips Related Errors

💡 What is Error 4404?

Windows System Error Code 4404, known as ERROR_APP_DATA_REBOOT_REQUIRED, is a DNS & WINS error that occurs during DNS resolution and WINS name resolution. The error indicates that: Fast Cache has been ReArmed and requires a reboot until it can be updated. When this error is encountered, the Windows operating system was unable to complete the requested operation within the DNS/WINS services subsystem. The error code 4404 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_APP_DATA_REBOOT_REQUIRED 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 DNS resolution and WINS name resolution is essential for effective troubleshooting.

⚠️ Common Causes

  • Windows Update cache is corrupted (SoftwareDistribution folder)
  • Required update services (BITS, Cryptographic) are stopped
  • Insufficient disk space for the update to install
  • Third-party antivirus is interfering with the update process
📚 Comprehensive Guide

The Complete Windows Event Viewer Masterclass for Crash Investigation

A deep dive into parsing the Windows Event Viewer, filtering DCOM / Service Control Manager logs, and finding the true root cause of silent application crashes.

Read the full guide →

✅ Step-by-Step Solutions

1 Reset Windows Update Components
  1. Open Command Prompt as Administrator
  2. Run these commands in order:
  3. net stop wuauserv
  4. net stop cryptSvc
  5. net stop bits
  6. ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
  7. ren C:\Windows\System32\catroot2 catroot2.old
  8. net start wuauserv
  9. net start cryptSvc
  10. net start bits
  11. Retry Windows Update
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Show Advanced Solutions (2 more)
2 Use Windows Update Troubleshooter
  1. Open Settings → Update & Security → Troubleshoot
  2. Click 'Additional troubleshooters' → 'Windows Update' → Run
  3. Follow the prompts and apply all suggested fixes
  4. Restart your computer and check for updates again
3 Manually Install the Failed Update
  1. Note the KB number of the failed update from Windows Update history
  2. Visit https://catalog.update.microsoft.com
  3. Search for the KB number and download the correct version (x64/x86)
  4. Double-click the downloaded .msu file to install manually
  5. Restart your computer

🎬 Video Tutorials

▶️ Watch Video Tutorials
How to fix Error 4404 (App Data Reboot Required)
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💻 Diagnostic Command

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

Get-EventLog -LogName System -Newest 20 | Where-Object {$_.Message -like "*4404*" -or $_.Message -like "*ERROR_APP_DATA_REBOOT_REQUIRED*"} | Format-List

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

🛡️ Prevention Tips

  • Keep at least 20GB free on your system drive for Windows Updates
  • Install updates promptly — don't let them accumulate for months
  • If updates consistently fail, consider a Windows in-place repair upgrade
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Last updated: 2026-03-18
📖
Based on Official Microsoft Documentation
Solutions Tested on Windows 10 & 11
Error codes sourced from Microsoft Win32 SDK. Updated 2026-03-18.
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