Prototype 2 was released in 2012 and does not always recognize modern cloud-synced file paths or non-English characters in Windows usernames. If Microsoft OneDrive is backing up your Documents folder, it changes the local path to something the game cannot read. Unlink OneDrive Protection Click the in your Windows taskbar tray. Go to Settings (gear icon) > Settings .
Which you are currently running (Windows 10 or 11)? If you are using OneDrive to sync your Documents folder? prototype 2 failed to save data fix