Some antivirus block legitimate Autodesk installers. Disable real-time protection only during installation, then re-enable.
Fix: Run Autodesk License Manager repair (Start Menu → Autodesk → License Manager → Repair). autocad 2018 download and install permanently link
To download and install AutoCAD 2018, use the official Autodesk Education portal or your paid Autodesk account. While a traditional "buy once, keep forever" license is no longer sold by Autodesk, the Education license provides renewable, free access for students, which is the most reliable "permanent" solution available today. Some antivirus block legitimate Autodesk installers