To make your Shadow Defender key code work, follow these official steps:

Copy your registration code from your purchase email and paste it into the "Serial Number" field.

Launch the application from your desktop or start menu.

It takes a snapshot of your disk and redirects all system changes—including file deletions, software installations, and malware infections—to a virtual environment.

Even while in Shadow Mode, you can manually "commit" a file to the real system, ensuring it survives the next reboot. How to Register and Activate