First, confirm that the device complies with the Windows upgrade requirements, including TPM 2.0, Secure Boot, compatible CPU and at least 64 GB of storage space; 2. Run Windows Update Troubleshooting Tools to fix update service issues; 3. Run DISM and SFC commands as administrator to repair component storage and system files; 4. Update or uninstall drivers that may cause conflicts, especially storage, chipsets, and graphics card drivers, and temporarily remove third-party security software; 5. Delete temporary files in the $Windows.~BT, $Windows.~WS, WindowsThe installation failed in the SAFE_OS phase during Windows upgradeTemp, and SoftwareDistributionThe installation failed in the SAFE_OS phase during Windows upgradeDownload folders; 6. Perform a clean boot, disable all non-Microsoft services and startup items and try the upgrade again; 7. If it still fails, use Microsoft's official media creation tool to upgrade on-site or install cleanly via USB boot; 8. Check the error details in the C:$Windows.~BTThe installation failed in the SAFE_OS phase during Windows upgradeSourcesThe installation failed in the SAFE_OS phase during Windows upgradePantherThe installation failed in the SAFE_OS phase during Windows upgradesetupact.log log file to locate the specific cause of failure; ultimately, if all methods are invalid, it is recommended to back up the data and cleanly install it to completely solve the problem.

If you're seeing the error "The installation failed in the SAFE_OS phase" during a Windows upgrade (such as upgrading to Windows 11 or a major feature update), it typically means the setup process encountered a critical issue while trying to configure the operating system in a secure environment. This phase occurs after the initial installation files are in place and the system begins applying settings and drivers in a protected mode.

Here's what you need to know and how to fix it:

? Common Causes of SAFE_OS Phase Failure

• Corrupted system files (like those in the Component Store)
• Incompatible or faulty drivers
• Third-party security software interfering
• Disk errors or storage issues
• Pending updates or incomplete previous installations
• Hardware incompatibility (especially with TPM, Secure Boot, or CPU)

? Step-by-Step Fixes

1. Check Upgrade Compatibility

Make sure your PC meets the minimum requirements for the version of Windows you're installing.

• Use the PC Health Check app (for Windows 11) or check:
  • TPM 2.0 enabled in BIOS/UEFI
  • Secure Boot turned on
  • Supported CPU
  • At least 64 GB of storage free

?? Even if your system seems capable, Microsoft's compatibility checks are strict — some older but capable CPUs are blocked.

2. Run Windows Update Troubleshooter

• Go to Settings > System > Troubleshoot > Other troubleshooters
• Run the Windows Update troubleshooter
• This can resolve underlying update service issues

3. Clean Up Component Store

A corrupted component store ( CBS ) can cause SAFE_OS failures.

Open Command Prompt as Administrator and run:

 DISM /Online /Cleanup-Image /CheckHealth
DISM /Online /Cleanup-Image /ScanHealth
DISM /Online /Cleanup-Image /RestoreHealth

Then run:

 sfc /scannow

This repairs system files and ensures the installer has clean base components.

4. Update or Remove Problematic Drivers

Outdated or incompatible drivers (especially storage, chipset, or graphics) can cause SAFE_OS crashes.

• Update drivers from your PC manufacturer's website (or motherboard vendor if custom build)
• Pay special attention to:
  • Intel Management Engine / AMD PSP drivers
  • NVMe SSD firmware/drivers
  • Graphics drivers (NVIDIA/AMD/Intel)

Alternatively, uninstall third-party antivirus or security tools temporarily.

5. Clear Pending File Renames and Staged Files

Sometimes leftover update files or pending operations interfere.

• Delete contents of:

   C:The installation failed in the SAFE_OS phase during Windows upgrade$Windows.~BT
  C:The installation failed in the SAFE_OS phase during Windows upgrade$Windows.~WS
  C:The installation failed in the SAFE_OS phase during Windows upgradeWindowsThe installation failed in the SAFE_OS phase during Windows upgradeTemp

• Also clear:

   C:The installation failed in the SAFE_OS phase during Windows upgradeWindowsThe installation failed in the SAFE_OS phase during Windows upgradeSoftwareDistributionThe installation failed in the SAFE_OS phase during Windows upgradeDownload

  ? You may need to take ownership of these folders or boot into Safe Mode to delete them.

  6. Perform a Clean Boot

  Prevent background apps from interfering:

  • Press Win R , type msconfig
  • Under Services , check Hide all Microsoft services , then click Disable all
  • Go to Startup tab → Open Task Manager → disable all startup items
  • Restart and try the upgrade again

  7. Use the Media Creation Tool (Clean Install Option)

  If in-place upgrade keeps failing:

  • Download the Media Creation Tool from Microsoft
  • Create a bootable USB
  • Choose Upgrade this PC now from the USB (keeps files/apps)
  • Or perform a clean install (back up data first)

  This bypasses many upgrade blockers and starts fresh.

  ---

  ?? Pro Tip: Check Setup Logs

  To pinpoint the exact failure:

  • After failure, go to:
    C:The installation failed in the SAFE_OS phase during Windows upgrade$Windows.~BTThe installation failed in the SAFE_OS phase during Windows upgradeSourcesThe installation failed in the SAFE_OS phase during Windows upgradePantherThe installation failed in the SAFE_OS phase during Windows upgradesetupact.log
  • Open the file and search for:
    • Error
    • Exception
    • Failed
    • SAFE_OS

  Look for the last few entries before the crash — it might reveal a specific driver or process causing the issue.

  ---

  Final Notes

  The SAFE_OS phase is one of the final and most sensitive stages of Windows setup. It's designed to be secure, which means it's also less forgiving of inconsistencies.

  If all else fails:

  • Backup your data
  • Use a bootable USB to perform a clean install
  • Reinstall apps afterward

  This often resolves issues that in-place upgrades can't fix.

  Basically, it's not just an error — it's the system protecting itself from a potentially unstable upgrade. Address the root cause, and you'll get through it.

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