Graphisoft no longer supports it. It will not run properly on modern Windows 11/10 (or macOS beyond Catalina) without serious compatibility issues. Downloading "free" full versions from unauthorized sites (torrent, warez, cracked) is illegal in Hungary and most countries, and extremely dangerous — such files commonly contain ransomware, keyloggers, or miners.
If you genuinely need ArchiCAD 16 for legacy file conversion or learning, here are the legal options: magyar archicad 16 ingyen letoltes top