I should add that I am receiving new emails fine and outgoing also works. It’s simply the transfer of existing emails from old Cox that is bad. I used Apple mail with my old Vox account and never had a size limitation. The issue lies with Yahoo and Apple relationship in my opinion.
Yes, quite a few folks have run into this issue of a storage limit. I don't know whether this happened when Cox migrated the files or when Yahoo ingested them but clearly files were either truncated or lost. Having spent years in IT I sympathize. It is, however, a reminder about the need for backups--and email hygiene. I use local mailboxes and store about 1.5k of old messages --which I routinely review and purge as appropriate.
