I recommend the professional, easy-to-use method that ToolsBaer Compress PST offers to shrink Outlook Personal Folder PST files. It works with all versions of Windows, including 10, 8, 7, XP, and more. It can work with both ANSI and Unicode PST files. It's possible to reduce the size of all the huge PST files without any limits. There aren't many limits on data. This app works with all versions of MS Outlook, including 2003, 2007, 2010, 2013, and 2016. Use the free test version to try things out.