We have a user running Win7 Professional (32-bit) with Outlook 2007. I believe every time the user either shuts down, or logs off (The problem happens infrequently) he is prompted with the error: "The data file * was not closed properly. The file is being checked for errors." This data file in question is the users mailbox, not a .PST file. We have tried deleting and creating a new profile, deleting said OST, etc. and this solves the problem for a few days or so, until it comes up again.