If you open MS Outlook and see an error message, Outlook is using an old copy of your Outlook data file (.ost), then use ...

Selective Recovery Option: Select the specific mailbox folders that you want to recover, such as the Inbox or Sent Items.

Your Outlook emails might be moved to the Junk folder. Check this. If you find your emails there, move them to the Inbox. Right-click on the email and select Move to > Inbox. You might have ...