zhizhu
Home / developer-tools / Windows Defender Not Opening on Windows 11: How to Fix - Troubleshoot Windows Update Certificate Error After Changing Clock-How to Fix Windows Defender Scan Stuck at 85% or 99%

Windows Defender Not Opening on Windows 11: How to Fix - Troubleshoot Windows Update Certificate Error After Changing Clock-How to Fix Windows Defender Scan Stuck at 85% or 99%

2026-06-13 13:47:23
Windows Defender Not Opening on Windows 11: How to Fix - Troubleshoot Windows Update Certificate Error After Changing Clock-How to Fix Windows Defender Scan Stuck at 85% or 99%

Result check

  • Keep one change per test run so you know which step helped.
  • Undo temporary changes after the issue is confirmed.

Next references

Windows Defender Scan Stuck at Certain Percentage: Fixes That WorkFix Windows Security DNS Error Blocking Internet AccessHow to Fix Firefox Not Responding on Windows 10Fix 'Connection Refused' Error in Windows Security for Remote DesktopFix Windows Security Offline Installer Sync IssuesFix Windows Defender Error 0x800704ec