Question Author
Yes thanks for your contributions.
My old machine runs on XP with Outlook Express. My new machine runs on 8.1 with Outlook 2013.
I have just done a couple of tests:
On my old machine I receive an e-mail, read it and delete it. Open up my new machine, click “Send/Receive” and the message is downloaded to my Inbox.
On my new machine I receive an e-mail, read it and delete it. Open up my old machine, click “Send/Receive” and the message is not found.
It is clear that when deleting a message using my new machine it is deleted from the server. The old machine does not do that. I have just found where, when setting up my old machine, there was an option to retain deleted messages on the server. It is under “Tools”, “Accounts” “Mail” Properties”. There is a tick box “Leave a copy of message on server”. (This seems something similar to your features, AOG).
However, my old machine suggests my account is of the POP3 variety. When I look on my new machine it suggests it is IMAP/SMTP (though I have only one e-mail account and have not changed anything).
Could this be the problem?