You don't really have any choice in how emails are sent to you. You can choose how to view them, regardless of how they were composed, though some commercially generated messages have only an HTML part for the content, and a plain text bit that tells you that you need a better email client.

In the menu, View|Message body as lets you choose the viewing mode.

The default composition mode is set in Tools|Account Settings... Composition & Addressing.

This is set per account, so if you have been able to set up one account just for this particular correspondence, that's where you'd set it not to use HTML.

Additionally, in the address book, when you look at any single contact's details, there is a setting to mark that correspondent's preference, so set that for plain text too.

And furthermore, though I can't give you the precise route to it right now, somewhere under Options is a setting called Send Options, which lets you choose between plain and HTML according to the domain in the addressee's email address. Look under Tools|Options|Composition.

Sorry Zenos but my question was concerned with sending emails(Mozilla thunderbird) not receiving/viewing.Should of made that clear.

Yes ,I set up plain text in "send options,"because genealogy mailing lists require posts in plain text.For some unknown reason a posting to one list has been rejected 3 times and so I will try again by working my way thru Tools/Options/compositions and so on.What I am asking is will this next try with this particular list cancel out the previous ones (maybe I made mistakes doing the send option with this recipient).If it doesn't cancel out my previous tries I risk being rejected again. Another Question: I have set up the send options (mail in plain text with several mailing lists -is there a way of checking proposed email recipients to make sure I have arranged for the text to be converted to plain text.I can't see anywhere where there is a record of domain names that have been programmed to receive plain text. I have set up a number of mailing lists to receive plain text but have not kept a record of such. I hope you can follow this. Many thanks. Trev.

To make sure a specific email address gets plain text. Is the email address in your address book ? If yes: open 'Address Book' select address book double click on contact/email address to open 'Edit contact' window. On the first 'Contact' tab, at the bottom... 'Prefers to receive messages formatted as: select 'plain text' click on OK

To make sure all emails sent to a specific domain name use Plain Text: Tools > Options > Composition > General tab click on 'Send Options' button click on 'Plain Text domains' tab When you send a message to an address with one of the domain names listed below, Thunderbird auto sends the message in the correct format' click on 'Add' enter the part after the @ of the email address - the domain name. click on OK to add to list. click on Ok to close Send options click on OK to close Options.

The list of Plain Text domain names will show what you have already entered, so if you need to remove, you can select domain name and click on 'Delete'.

You can also choose to compose in Plain Text.

If you usually compose using HTML and have the Formatting Bar etc, but you want to compose a specific email in Plain Text. Hold down 'Shift' key and click on 'Write'. This will allow a one off plain text email.

Solved in that I can ensure that if I need to send in plain text (And I'm not sure that I have already done so i.e. had a memory lapse) I can do so in various ways so thank you for your answers-most helpful.

Trev.