If you only want to change the default account - the one at the top is the default account. Tools > Account Settings or Meu icon > Options > Account Settings select the account name click on 'Account Actions' select 'Set as default' click on OK If you want to do more rearranging then you need to use this addon: * https://addons.mozilla.org/en-us/thunderbird/addon/manually-sort-folders/ Download addon to dektop or downloads folder In Thunderbird Tools > addons or menu icon > addons click on gear wheel icon and select; Install addon from file locate the file you downloaded and click on open You may need to restart Thunderbird.

Thanks Toad.