Autocad 2015 Portable ((free))
The file is not AutoCAD. It is a remote desktop client or a script that opens a connection to a cracked server. When you run it, you see an AutoCAD interface, but all processing happens remotely. Without an internet connection, it shows an error.
Simply put: A legal, official portable AutoCAD would cannibalize their cloud subscription revenue. Autocad 2015 Portable
Beyond performance, "Autocad 2015 Portable" is a vector for cyber threats. Security researchers (Kaspersky, McAfee, 2020–2024 reports) consistently find that over 75% of cracked portable CAD downloads contain additional payloads. The file is not AutoCAD