How to fix 2020-12 Cumulative Update for Windows 10 Version 1903 for x64-based Systems (KB4592449) - Error 0x800f0900 and 2021-09 Update for Windows 10 Version 1903 for x64-based Systems (KB 4023057) - Error 0x800f0900?

Question

Hello, for a couple of years I've been trying to update my Windows it never lets me. When I get to the blue screen, I try every option and yet it still won't allow me to update, from recovery to full reset, my computer won't allow me. It's hard for me to download new apps since I can't update my computer. When I go into settings I have two problems that will consistently not update. One of them is named: 2020-12 Cumulative Update for Windows 10 Version 1903 for x64-based Systems (KB4592449) - Error 0x800f0900. The second one is named: 2021-09 Update for Windows 10 Version 1903 for x64-based Systems (KB 4023057) - Error 0x800f0900. I have tried to search up ways to resolve the issue, but none of them work. I've tried going through the Device Manager and writing several lines (which most of them get a response saying access denied) and Command Prompt as well (same response). I cannot update my computer to even try to resolve the issue. What should I do? I need extreme help. Thank you.

Answer 1

Here’s a systematic, step-by-step protocol to troubleshoot and resolve the 0x800f0900 errors when installing KB4592449 and KB4023057 on Windows 10 Version 1903:

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1. Verify Your Current Build & Free Up Space
2. Press ⊞ Windows + R, type winver and press Enter.
   • Ensure you really are on Version 1903 (Build 18362.x).
   Check you have at least 20 GB free on your Windows drive (C:). Low disk space often blocks cumulative updates.

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2. Run Windows Update Troubleshooter

Settings → Update & Security → Troubleshoot → Additional troubleshooters.

Select Windows Update → Run the troubleshooter.

Apply any fixes it suggests, then reboot and retry Windows Update.

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3. Repair the System Image (DISM & SFC)

Corrupted component store or system files commonly trigger 0x800f0900. Run these from an elevated Command Prompt:

DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow

/ScanHealth and /RestoreHealth inspect and repair the Component-Based Servicing (CBS) store.

sfc /scannow fixes protected system files.

Reboot after these complete, then try Windows Update again.

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4. Reset Windows Update Components Manually

If DISM/SFC didn’t help, fully reset Windows Update:

Open an elevated (Admin) Command Prompt.

Stop Update services:

net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver

Rename cache folders:

ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old

Restart services:

net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Reboot, then check for updates again.

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5. Download & Install the Stand-alone Packages

If Windows Update still fails:

Go to the Microsoft Update Catalog:

KB4592449: search “KB4592449” → download the x64 MSU installer for Version 1903.

  KB4023057: search “KB4023057” → download the **x64** MSU.
  
  Run each MSU installer **as Administrator**, in chronological order (KB4592449 first, then KB4023057).
  
  Reboot between installations.
  

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6. In-Place Upgrade to a Supported Release

Version 1903 went out of service in December 2020. If the above still fails, perform an in-place upgrade to a newer Feature Update (e.g., 21H2 or later):

Download the Windows 10 Media Creation Tool from Microsoft.

Run it, choose Upgrade this PC now, and follow the prompts.

When asked, opt to keep your files and apps.

After upgrade, you’ll be on a supported build—and all cumulative updates will install automatically.

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7. Final Checks

Event Viewer: After a failed update, open Event Viewer → Windows Logs → Setup to see more detailed CBS or SERVICING errors.

Antivirus/Encryption: Temporarily disable third-party AV or BitLocker, then retry.

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By following these steps—running the Update Troubleshooter, repairing the component store with DISM/SFC, resetting the update cache, manually installing MSU packages, and if needed performing an in-place upgrade—you should clear the 0x800f0900 error and get those cumulative updates successfully applied. Good luck!Here’s a systematic, step-by-step protocol to troubleshoot and resolve the 0x800f0900 errors when installing KB4592449 and KB4023057 on Windows 10 Version 1903:

---

1. Verify Your Current Build & Free Up Space

Press ⊞ Windows + R, type winver and press Enter.

Ensure you really are on Version 1903 (Build 18362.x).

Check you have at least 20 GB free on your Windows drive (C:).

  Low disk space often blocks cumulative updates.
  

---

2. Run Windows Update Troubleshooter

Settings → Update & Security → Troubleshoot → Additional troubleshooters.

Select Windows Update → Run the troubleshooter.

Apply any fixes it suggests, then reboot and retry Windows Update.

---

3. Repair the System Image (DISM & SFC)

Corrupted component store or system files commonly trigger 0x800f0900. Run these from an elevated Command Prompt:

DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth
sfc /scannow

/ScanHealth and /RestoreHealth inspect and repair the Component-Based Servicing (CBS) store.

sfc /scannow fixes protected system files.

Reboot after these complete, then try Windows Update again.

---

4. Reset Windows Update Components Manually

If DISM/SFC didn’t help, fully reset Windows Update:

Open an elevated (Admin) Command Prompt.

Stop Update services:

net stop wuauserv
net stop cryptSvc
net stop bits
net stop msiserver

Rename cache folders:

ren C:\Windows\SoftwareDistribution SoftwareDistribution.old
ren C:\Windows\System32\catroot2 Catroot2.old

Restart services:

net start wuauserv
net start cryptSvc
net start bits
net start msiserver

Reboot, then check for updates again.

---

5. Download & Install the Stand-alone Packages

If Windows Update still fails:

Go to the Microsoft Update Catalog:

KB4592449: search “KB4592449” → download the x64 MSU installer for Version 1903.

  KB4023057: search “KB4023057” → download the **x64** MSU.
  
  Run each MSU installer **as Administrator**, in chronological order (KB4592449 first, then KB4023057).
  
  Reboot between installations.
  

---

6. In-Place Upgrade to a Supported Release

Version 1903 went out of service in December 2020. If the above still fails, perform an in-place upgrade to a newer Feature Update (e.g., 21H2 or later):

Download the Windows 10 Media Creation Tool from Microsoft.

Run it, choose Upgrade this PC now, and follow the prompts.

When asked, opt to keep your files and apps.

After upgrade, you’ll be on a supported build—and all cumulative updates will install automatically.

---

7. Final Checks

Event Viewer: After a failed update, open Event Viewer → Windows Logs → Setup to see more detailed CBS or SERVICING errors.

Antivirus/Encryption: Temporarily disable third-party AV or BitLocker, then retry.

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