Visual Basic for Applications Reference

Form already displayed; can't show modally (Error 400)

Specifics

You can't use the Show method to display a visible form as modal. This error has the following cause and solution:

• You tried to use Show, with the styleargument set to 1 vbModal, on an already visible form.

  Use either the Unload statement or the Hide method on the form before trying to show it as a modal form.