How do I get archived emails back

[#1]

Hello all, thanks for your responses and the useful info.  I am using webmail only currently, but I was previously using Outlook Express which I think may be the reason I believed my emails were archived as I think that was a POP3 setup.  That was corrupted in January 2020 hence I started using webmail only from that point on.  So it looks like I'm not going to get them back now.  Ho hum.

[#2]

@jgalloway The extra information you have given above ( file corruption) throws a completely different light on things. Unfortunately, unless you backed those emails up elsewhere, they are gone.