If emails are showing a load of headers and html then try this: * right click on Inbox folder and select 'Properties' * Click on 'Repair Folder' button * Click on 'OK' BUT...If emails look more like a saved draft which you edit then it sounds like a 'drafts' flag has been set on the 'Inbox'. The easy way to fix is to use an addon called 'Folderflags'. Install this add-on to correct the properties: * https://addons.thunderbird.net/en-us/thunderbird/addon/folderflags/ Some images below may assist when installing that 'Folderflags' addon. The first image should help if you actually downloaded the xpi file from the link above. The following 3 images may helps if you want to auto installed from a Thunderbird search and rest apply either method.