I recommend you utilize this Outlook PST compress application, which can safely decrease the size of your Outlook mailbox without the requirement for Microsoft Outlook installation. It can compress Outlook/Exchange OST/PST files, handle single or multiple PST files, and display full folder information. The features include compressing attachments into a new PST file, eliminating duplicate emails, and managing attachments. This Aryson PST compress utility has clever filtering, file splitting by size, and a date range option. It is also compatible with all Microsoft Outlook versions for the Windows operating system.