Ensure your external HDD/USB is formatted to NTFS (MBR partition scheme is recommended).
prepntfs.pkg is a small but crucial piece of Apple’s Boot Camp infrastructure. Unless you are troubleshooting a failed Windows installation on an Intel-based Mac, you will likely never need to interact with it directly. prepntfs.pkg
In short, prepntfs.pkg is designed to for Windows installation on a Mac. It is not a standalone application or a virus; it is a tool that runs in the background, typically triggered by the Boot Camp Assistant or during certain macOS system updates. Ensure your external HDD/USB is formatted to NTFS