AutoCAD *virus* ????

I am a networking consultant working with a large architectural firm.
They have run into an AutoCAD problem that I have never heard of
before and don't have the foggiest idea where to begin. I haven't
worked with CAD -especially AutoCAD- in years so I thought I'd post a
summary and see if anyone has heard of this one.

Although I've never heard of a virus affecting CAD files, this
phenomenon sounds almost viral in nature. The problem seems to be
spreading around the office. First it was one person, then their
project team now loads of people.

The first symptom, which appeared a few days ago, was that the XREF
dialog box would not appear. When "XREF" is entered at the command
line, the resulting prompt is "Specify block to insert." The second
problem that appeared today is that the affected users can not explode
any blocks at all. No error is reported, the block just remains the
same.

Some users are still fine but once affected (infected?), they stay
that way.

Any and all help would be appreciated.

-Bruce

 

Thanks for your help Paul,

We seem to have a rogue acad.lsp file that is propagating into all of
the project folders on the network. It is small (3kb) and we don't
know where it is coming from. Below is a sample of the first 10 lines
or so:

(defun
s::startup
(/
old_cmd
path
dwgpath
mnlpath
apppath
oldacad
newacad

Prepending XREF or Explode with a period (e.g., ".explode") results in
the command working as designed. Any idea what could be generating
the bad .lsp file?

Thanks again,

Bruce