Willy,

>Suggestions (other than re install VStudio again) are welcomed.

<s> Yes, that reinstall is a royal pain in the neck!

I haven't seen this behavior before, so that's why I recommended the reinstall of VS...something is definitely happening on your machine that's unique. Maybe you can narrow it down a bit...are you working with a solution that has multiple projects in it? If so, does the error occur if you open the Business Object solution (with no other projects)? Does it happen after you run the application or instantiate business objects? If so, is there something in your application that might be locking the file?

Best Regards,