Short answer is place Thunderbird into offline mode before generating mail (click the two blue monitors in the bottom left of the screen) That will cause all mail to be placed in the outbox folder and force a send later mode

Once mail is generated, go back online by clicking the monitors again and sending will not fall over itself. Should you forget to go online, Thunderbird will prompt you to send all unsent mail when you close it.

Thanks for the reply Matt, have tried that now - but it seems that with MT offline the mail doesn't make it into the outbox at all.

What could be that cause of that do you think?

Have you found the outbox folder? It will be under local folders.

Is there anything in the error console? Tools menu (alt+T) > error console Clear it then try the send as it always contains loads of rubbish

Thanks - I got the following errors:

aDocumentNode.cardDetails.cardDetails is undefined

Exception ... "componenet returned failure code:0x8004011 (NS_error_Not_avaialable)

BUT - then found a bug related to the top one on bugfix - it is for a older version. So I updated TB to current version and - boom - all working.

Thanks for you input Matt