Windows Update error 0xC80003F3 occurs when update components are blocked or corrupted. Here's a simple, streamlined fix:
1. Reset Update Components
Open Command Prompt as administrator and run:
net stop wuauserv
net stop bits
net stop cryptsvc
ren C:WindowsSoftwareDistribution SoftwareDistribution.old
ren C:WindowsSystem32catroot2 Catroot2.old
net start wuauserv
net start bits
net start cryptsvc
2. Run the Windows Update Troubleshooter
Go to Settings → Update & Security → Troubleshoot, select Windows Update, and run the tool to automatically fix common issues.
3. Repair System Files
In the same elevated Command Prompt, execute:
sfc /scannow
This checks and repairs corrupted Windows files that may block updates.
4. Disable Antivirus/Firewall Temporarily
Security software can interfere with update downloads—turn it off, check for updates, and then re-enable protection.
5. Restart and Retry Windows Update
Reboot your PC and head to Settings → Update & Security → Windows Update to try installing updates again.
For a complete, step-by-step walkthrough, including advanced troubleshooting options, visit this detailed guide.