program auto-loads whenever I save a document

I cannot find the answer to this - I think I am searching under the wrong words and would appreciate some help.

Every time I rename a PDF or save a Word document as a PDF, Adobe Acrobat automatically opens a copy of the saved PDF. I want this to stop - I find it really annoying.

I can't find this option in Preferences, can someone tell me how to disable it?

Thanks!