The Windows 8.1 upgrade will not complete or an error message appears stating Windows 8.1 cannot be installed.

During upgrade from the Windows® 8 operating system to Windows® 8.1, it is important to make certain the upgrade process is not interrupted. The upgrade process consists of two stages:

• Extraction of Windows 8.1 upgrade files and copying of these files to the system drive of the computer.
• After the computer restarts, Windows 8.1 will launch a setup wizard for setup of user profile and preferences.

If either part of this process is interrupted, the computer will attempt to revert (roll back) to the previous version of the operating system, in this case Windows 8. This reversion should not result in loss of data.

IMPORTANT:

• Before installing Windows 8.1, to properly prepare your computer for the Windows 8.1 upgrade and help prevent interruptions during upgrade, please follow the recommended Sony upgrade instructions at the Sony website. Downloads are posted on your model support page. .
• For any VAIO® computers that contain a battery, before attempting the upgrade, make sure the computer is connected to the AC adapter and the AC adapter is plugged in to a working wall outlet.

If the upgrade process continues to fail, or error messages persist during or after the Windows 8.1 upgrade process, follow these steps:

NOTE: Several of the steps below require the computer to be connected to the Internet.

1. Open the VAIO Update application on the computer, check for and install all available updates.

   NOTE: If the VAIO Update application is not available or not working, download and install all available updates. Downloads are posted on your model support page.

2. Open the Windows Update  utility on the computer and install all available Windows updates.

   NOTES:

   • After installing all available updates, restart the computer, and then check for updates again.
   • Because some Windows Updates are dependent on others to be installed first, after installing updates and restarting the computer, more updates may appear.
3. Remove and reinstall  any device that may be causing a conflict in Device Manager.
4. Disable all Startup applications  from the Task Manager.
5. If necessary, uninstall any Internet Security software.
   • Turn on the Windows Firewall for protection while Internet Security software is uninstalled.
   • After upgrade is complete, reinstall Internet Security software and check for a Windows 8.1 compatible version of this Internet Security software.