Hi,
when you speak about a "new file" you mean a new drawing from a template?
If yes, try first with a diffenrent original template out of template directory.
If no and you mean a existing drawing, then please open the drawing with recovering and let autocad repair issues found.
Maybe that helps.
Third option is you have a server based profile. In that case you have to check a different user.
Last idea is do you deactivate your virus scanner during installation? If no try it.
Thorsten
