If you look at a PST file’s properties on a Windows system, it will be listed as an Outlook Data File. Locating Your Mail Archive Folder If you are not sure whether or not you have mail stored in archive files, you will need to open your Outlook email client and look at the inventory of folders on the left side. For Outlook 2010, 2013 and 2016, you will need to make sure that the Home tab is selected.