Right-click AutoCAD icon > Properties > Compatibility > Run this program as administrator. Also, reinstall the FLEXnet licensing service: delete C:\ProgramData\FLEXnet folder (backup first).
Because of the activation and compatibility hurdles, Autodesk recommends moving to current solutions: Problem when I'm installing AutoCad 2014 - Forums, Autodesk Autodesk AutoCAD 2014 Download
Not directly from Autodesk’s main product pages. Right-click AutoCAD icon >