Yet again, thanks for the trouble taken to resolve my problems. My server settings are POP3.Live.com for the 3 Hotmail accounts (and POP3.btinternet.com for the Yahoo/BT account). From what you say that is wrong.
Eugene emailed me directly to indicate there are at least 3 types of hotmail account and I should have used "Add other account" available from the bottom left tab of the Account settings box. I had used "Create a new account" to set up. I have been playing with that method exploiting an empty Hotmail account and ran into an issue that when I checked Account settings it then said "local host" in server name. I edited that to POP3 as above - but don't seem to be receiving emails in that account. Looks as if I have taken (almost) every wrong turning possible! If I have to start again on Tbird, the troublesome trial of Outlook available for a week more which makes imports easier. Sandy
