How do I turn off "document preparation" in Acrobat XI?

I think I may have accidently turned on an option a few months ago and I want to turn it off.   It appears that, whenever I open a PDF, Acrobat starts to prepare the document for something.  There is a window that pops up on my screen almost immediately after opening that says, "Please wait while document is being prepared."  It then shows the page numbers as it "prepares" the document.   It normally only takes 5-10 seconds to prepare a 10-page document, but a long document can be very disruptive.  I am given the option to cancel the process, but this often locks up Acrobat and I have to close the app.

What is going on and can I stop it.  Should I stop it?  I don't really know what it is doing.   I have noticed that the window that displays the above message does not indicate which application the message is coming from, so it is possible it is not an Adobe message.

Thank you.