I've been using eSoftTools Outlook PST Recovery Software to fix the Outlook Inbox not showing all emails issue. All of your Outlook emails, contacts, attachments, calendars, and notes will be exported to a new PST file, allowing you to access all of your Outlook data once again. This application can break down large PST files into smaller files. You can recover up to 25 emails per folder with the trial version of this program.
Read more:- Fix “Outlook Inbox Not Showing All Emails”