First let's check to see if it is simple case of there being a missing mbox file. I'm assuming this is a POP mail account in which case do the following, so tell me if not POP. I would need to see what you currently have got stored in the profile to understand what is going on. In Thunderbird * Help > Troubleshooting Information * click on 'Open Folder' button a new window opens showing the contents of your 'profile name' folder. * click on 'Mail' folder * click on the pop mail account name folder to see contents. Make sure the window is big enough to show as many files and folders as possible. * Post an image(s) showing the entire contents of the 'pop mail account name' folder. If you see a folder with a '''missing folder name.sbd''' extension which has same name as the missing folder: * Click on the *.sbd folder to see contents. * Does it list files that seem to have same names as the missing subfolders? * Post an image(s) showing the entire contents of the .sbd folder(s). Tell me the name of the missing folder that contains all the missing subfolders.