This means that any file labeled "Portable AutoCAD 2016" you find online is almost certainly a cracked, modified version. Downloading and using such versions exposes you to a host of serious risks:
A dedicated, lightweight open-source application for 2D geometry. Download AutoCAD 2016 Portable 64 Bit
This public link is valid for 7 days and shares a thread, including any personal information you added. This link or copies made by others cannot be deleted. If you share with third parties, their policies apply. Can’t copy the link right now. Try again later. This means that any file labeled "Portable AutoCAD