While upgrading an older version of the Windows operating system to a higher version of Windows OS, like Windows 11 or Windows 10, or while installing updates, some users have encountered the 0x80071AA8 – 0x2000A, Installation failed in SAFE_OS phase error. The complete error message that pops up on the screen while upgrading or updating Windows is:

Error 0x80071AA8 – 0x2000A, Installation failed in SAFE_OS phase with an error during PREPARE-SAFE-BOOT operation

If you receive this error while upgrading to the higher version of Windows, one possible cause of this issue is you are installing Windows OS on a different hard disk, say an SSD but your user profile is on a different hard disk, say an HDD. Apart from this, there are other causes too that can trigger this error. In this article, we will see some solutions to fix the error “0x80071AA8 – 0x2000A, Installation failed in SAFE_OS phase” on Windows PC.

What is the SAFE_OS phase?

When you turn on your computer, first, the firmware settings are loaded and a disk system check is initiated. In the next step, the operating system is loaded by the Windows Boot Manager. After that, WinLoad.exe loads important drivers to start the Kernel which loads the registry settings and additional drivers and gives control to the system manager process. Now, your UI and the rest of the software are loaded and you see the login screen. The SAFE_OS phase is the stage where the system verifies that everything including the drivers is working fine as expected. During this phase, if anything insecure is found or if any of the signatures are missing, you may get the installation failed in the SAFE_OS phase error.

Read: Description of the Windows boot process

What is the PREPARE-FIRST-BOOT operation?

The First Boot operation enables a computer to load an operating system either from the internal hard disk or from the external hard disk or pen drive connected to it. The boot order can be changed in the BIOS setting.

Error 0x80071AA8 – 0x2000A, Installation failed in SAFE_OS phase

If you are upgrading to the higher version of Windows and you receive this error, the Windows installation will be terminated. In such a case, revert back to the previous version of Windows and try the following fixes. After that, upgrade Windows or run Windows update again.

Before you proceed, make sure that your system fulfills the hardware requirements for the version of Windows OS you want to install. Also, check if all your drivers are up to date.

1. Run Windows Update Troubleshooter
2. Reset Windows Update Components
3. Temporarily disable your antivirus
4. Update Windows using Windows 10 Update Assistant
5. Change your BIOS mode from Legacy to UEFI
6. Create a new user account
7. Clean install Windows

Let’s see all these solutions in detail.

1] Run Windows Update Troubleshooter

Windows Update Troubleshooter is an automated tool developed by Microsoft that helps users fix the problems related to Windows Updates. You can access this tool via your Windows 11/10 Settings. Run the Windows Update Troubleshooter and let it detect and fix problems. When the troubleshooting process gets completed, check if you can install the Windows update.

2] Update Windows using Windows Update Assistant

If your system is running on Windows 11/10 and updating Windows 10 is failing due to this error, you can use Windows Update Assistant to install the latest Windows updates. Windows Update Assistant downloads and install the feature updates on a Windows device. You can download it from microsoft.com.

3] Reset Windows Update Components

Windows Update Components are the essential part of Windows update. If there is a problem with Windows Update Components, you will not be able to install the latest Windows updates and may get several errors while updating your system. One way to fix the Windows update problems is to reset Windows Update Components. After manually resetting the Windows Update Components to default, you should be able to install the latest Windows updates. If the issue still persists, there might be another reason for the problem. Try the next solution.

4] Temporarily disable your antivirus

Sometimes antivirus software prevents Windows from installing the latest updates. This is definitely a false positive flag from the antivirus. It might be possible that your antivirus is interfering with the Windows Update due to which you are receiving this error message. One way to check this is to disable your antivirus temporarily. If this fixes your problem, you can enable your antivirus after updating your system. If this does not work, you need to try some more troubleshooting methods. Hence, move ahead and try the next potential fix.

5] Change your BIOS mode from Legacy to UEFI

One effective solution to fix this problem is to enable UEFI mode in your system BIOS. For this, your BIOS should support the UEFI mode. You can check your system’s BIOS mode in the System Information console. To launch it, click on Windows Search and type system information. After that, select the System Information app from the search results.

If your BIOS mode is set to Legacy, change it to UEFI and check if it fixes the problem. To do that, your BIOS should support the UEFI mode. To check this, enter your system’s BIOS and select the BIOS mode option. If it shows both Legacy and UEFI, your system supports both Legacy and UEFI BIOS modes. Now, you can switch from Legacy to UEFI BIOS mode.

6] Create a new user account

If you have two hard disks installed on your system, say an SSD for Windows OS and an HDD for your user data. In this case, if your user profile is created on a hard drive other than the one on which Windows is installed, your system will not be able to find the path of your user profile and you will get this error message. To fix such a problem, modify a Registry Value and then create a temporary user account.

The step-by-step process is explained below.

Press the Win + R keys to launch the Run command box. Now, type regedit and click OK. Click Yes in the UAC prompt. This will open the Registry Editor.

When the Registry Editor opens up, navigate to the following path. To do so, copy the following path and paste it into the address bar of the Registry Editor. After that, hit Enter.

HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionProfileList

Make sure that the ProfileList key is selected on the left side. Right-click on the ProfilesDirectory Value on the right side and click Modify. Type %SystemDrive%Users in Value Data and click OK.

Close the Registry Editor and create a temporary local administrator account. Restart your computer from the newly created user account to install the updates.

The Windows updates should get installed this time without any error. After installing the updates, you can delete the temporary local administrator account.

7] Clean install Windows

If none of the above solutions fixed the error, a clean install of Windows OS will help. Do note that a clean install will erase everything from the drive on which you install Windows. Therefore, it is better to backup your data before you perform a clean install.

Hope this helps.

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