Migrating / Syncing iCloud Email to Exchange account I'm trying to migrate all mails and folder from a IMAP email to a another.
I selected all the folders and drag them to the new mailbox.

I can see some of the folder but not all the sub-folder, also when I check mailbox detail, the count is not the same.

the issue is I start moving some new mail to the new mailbox only.

How can I get the two mailbox completely synced ?

PS one is from iCloud, the another is from a exchange server.
I find the solution, it's was too obvious, but just Mailbox menu > Export mailbox 

and then can move them to correct account :  ~/Library/Mail/V4

(or import them from the menu)