- Keep your current anti-virus up-to-date, scan your system regularly and don't blindly open compacted files (like .zip files). Make sure that you anticipated the file and that the sender is a trusted source.
- Turn on Virus protection in AutoCAD. Enter VBARUN at the command line and click Options. The default is on, so unless you turned it off or someone turned it off for you you're fine. This protects you from embedded Visual Basic for Applications (VBA) macro viruses.
- Don't use strange LISP routines or add on programs from unknown sources without checking them first.
- acad2009doc.lsp: An Autodesk-provided file. Is installed with the program.
- acad2009.lsp: An Autodesk-provided. Is installed with the program.
- acaddoc.lsp: A user-created file. May or may not reside on your system.
- acad.lsp: An older file. May or may not reside on your system.
These files are fine if they were installed by your software, however, some people modify, and share them and that could get you in trouble if you don't know or trust that source.