I'm on the road so using my laptop, Windows 10, Office 365 Outlook.

When I set up my two emails a couple of years ago I used STMP/POP3 and NOT IMAP. Just did a send/receive and got a "xxx.net sending, xxx.net receiving, yyy.net sending, yyy.net receiving" along with 70+ emails, i.e. all the ones my $400 Office 2016 PRO Outlook had failed to deliver. There was no "synchronization" of any kind that took place....NONE

When I get back I'm going to delete all the IMAP email accounts and redo them with SMTP/POP3 data and see what happens.

Just for my own edification....what exactly is the purpose of the "synchronization of folders" anyhow? What is it supposed to do? Seems like whatever it is, I don't need it since without it I can actually download email!