Mail empty

Ewan Lamont wrote:

A new issue. I’ve been with Mac since 2000.

Quit Mail.app relaunch it holding the Shift key down, and compare your results...

For problem accounts the go to way to sort things out is to delete the account(s) from the Mail.app, then add it back.

Remove email accounts in Mail on Mac

Remove email accounts in Mail on Mac - Apple Support

Add email accounts in Mail on Mac - Apple Support

Add email accounts in Mail on Mac - Apple Support

Note—

IMAP accounts stay on the server, so no local loss, when you re-sync

POP accounts download and remove from the server—therefor save your inbox/sent box if you want them

“On My Mac" is just that, local folders you created and moved mail into. So no loss

Ewan Lamont wrote:

my inboxes are empty.. I know there should be an important email in one.

?

old issue, new issue, what changed... you do not paint a very big picture.

ref: