(like a specific LISP routine or old project format), use a Windows XP virtual machine instead of forcing a native install.
Installing AutoCAD 2006 on Windows 10 is by Autodesk, and you will encounter compatibility issues due to major changes in Windows architectures (e.g., deprecated components like the old .NET Framework 1.1/2.0, changes in activation servers, and 16-bit installer remnants). install autocad 2006 on windows 10