You are prompted to prepare Office Outlook 2007 for first use after you apply security update 972363

You apply security update 972363 that is documented in security bulletin MS09-060. When you open a Microsoft Office Outlook 2007 client that already has a .pst file or .ost file in the profile, you see a dialog box that states that Outlook is being prepared for first use. Additionally, you have to wait a long time for the process to finish.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.