Outlook has a bunch of commandline switches that can be used to change certain behaviors, reset settings, or do things such as create messages. There are two switches that are sometimes confused with each other: /cleanreminders and /resetfolders. I got an explanation of the difference between the two once, and wanted to share it:
outlook.exe /cleanreminders recreates the reminder search folder and restarts the search.
outlook.exe /resetfolders recreates the properties (and possibly the folders themselves) that point to the default folders. We cache the entry IDs for the default folders on the root of the store so that we don't waste RPCs looking them up every time we need one. /resetfolders causes us to look for a folder named “Inbox“ or “Calendar“ (or localized versions). If we find the folder, we stamp the entry ID for that folder into our special property for that folder. If we couldn't find a folder by that name, we create the folder and stamp the property. The reminders folder is one of our default special folders, so this applies to it, too.