In Options/General/Offline, change the startup state to offline.

Thanks and E--for Effort. Went to Tools, options, general and it say When thunderbird launches show the start page in the message area. I change the location to off line and I think it stopped the download. However. if I want to get messages later and I click on "Get Messages" it will not download any. Had to go back to the default to get it to download messages.------or am I still doing something wrong?

There's no need to change the start page setting; change the Offline settings as in the attached picture. To go online to get or send mail, click the icon at the left end of the Status Bar to toggle the network state between offline and online.

Thank you for your help but I can not find that image in thunderbird . If I click on off line settings it gives me the same popup as "view settings for this account" and I have looked everywhere for that image you attached and can not find it anywhere in my account settings.Maybe I need to re-download Thunderbird----maybe it did not all download correctly. I am just scared of loosing all my folders and the information. In the bottom I toggled it to be offline and closed my browser. ---but when I log back in it automatically downloads my emai whether I want them at the time or not.

If you're on TB 68, press Alt to show the Menu Bar, then Tools/Options/Advanced/Network & Disk Space/Offline/Offline...