I have 2.37GB of archived Outlook data that I saved in 2009 when I finished work. When I click any of the files to open them I get a window asking: 'How do you want to open this type of file (.pst)?' and 'Look for an App in the store' (my OS is Windows 8.1 x64bit). I no longer have Outlook Express (my company's email client at the time) and for what it's worth these days I have Mozilla Thunderbird. Can anyone tell me how I can open and read the information that I've archived, please?