This is not an actual AutoCAD file provided by Autodesk. When the malicious acad.vlx file
is loaded in AutoCAD, it corrupts the drawing, which may result in a
Missing Language Pack dialog box displaying when you save and reopen the
The acad.vlx file creates a copy of itself in the Help folder (for example, C:\Program Files\AutoCAD 20xx\Help\logo.gif). Several other files are also modified and the ACADLSPASDOC system variable is set to 1, allowing the acad.vlx file to be loaded into other opened drawings, thereby corrupting them.
The cleanup process outlined below detects and deletes any acad.vlx file before AutoCAD attempts to load it, preventing the spread of the virus.