Loss of emails after compacting

Don't know. Maybe compacting means that an original email with a dozen replies and rereplies are now shown as one email. If so, you could select that email and discover the whole chain.

In case someone else answers, it might help to give the name of your email service.

I think compacting is something that Microsoft Outlook does to the file where it stores emails on the hard drive.

But I have no familiarity with the process, so can't provide any answer about where to find the wayward emails.

Might be trouble. I hope it doesn't relate to compacting an email database.