Unruly Subfolder

In one folder in my Inbox where I save emails, there is a subfolder that always opens at startup. None of the other subfolders within that folder automatically open. When I close the unruly subfolder, it opens up again the next time I restart. Is there a way to convince this subfolder that he is not that important to me anymore? Also, some of the other folders in my Inbox automatically expand at startup, even though I had previously collapsed them.