My user prints his document to PDF (out of an Access 2007 DB) and leaves it open (at which point it is "saved" on the network drive). He then drags a one-page PDF to the page thumbnail window on the left. He then tries to delete one of the old pages in the original PDF. If he deletes it BEFORE he clicks on "save", he can delete the page without any problem.
But if he clicks on "save" and then tries to delete one of the old pages, he gets the following error statement:
"One or more pages are in use and could not be deleted".
Additionally, if he closes the original PDF and re-opens it, he can delete any page(s) he pleases.
He is using a copy of Acrobat X Pro that is fully updated. This behavior can be replicated on my machine with my copy of Acrobat X Pro.