If you 'Remove an account' via Account Settings, then you will not see that account in Thunderbird Folder pane nor Account Settings window because you have just selected to remove it. However, you should still see that account in your Profile name folder assuming you did not access it and delete it manually. If you removed in error, then you should be able to get it back. first check it is still in profile name folder. The profile is in Appdata folders which are usually hidden and may explain why you cannot see them. Make hidden files and folders visible: * http://kb.mozillazine.org/Show_hidden_files_and_folders In Thunderbird * 'Help' > 'TRoubleshooting Information' * click on 'Open Folder' It will open a new window, showing the contents of your current profile name folder. * Click on 'Mail' folder. You will see 'Local Folders' folder. You will also see POP mail accounts listed, assuming they exist. In Windows OS, by default they will be here: C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\Mail\<pop mail account name> If you have more than one email address using same server settings, you will see the 'Server Name' of the pop mail account, but subsequent ones will have a number added. eg: 'mail.btinternet.com' and 'mail.btinternet-1.com' You need to create a new pop account and connect it up to use the old one. So make a note of the pop mail account name which you want to access again. Create a new existing mail account set up as pop using same email address as before. In Thunderbird Menu icon > New Message > Existing mail account Once created before getting any new mails, you need to point that new pop mail account to use the directory where the old mail account is located. Right click on mail account in Folder Pane and select 'Settings' Select :'Server Settings' bottom right 'Local directory:' click on 'Browse' and locate the old original pop mail account. C:\Users\<Windows user name>\AppData\Roaming\Thunderbird\Profiles\<Profile name>\Mail\<pop mail account name> click on OK Once you can see everything again, Do you want to save those emails somewhere where you can access them, but you do not want to keep the pop mail account ? If yes, Create suitable folders in 'Local Folders' Move emails from pop account into Local Folders account. Delete any emails you do not want. Empty 'Junk' and 'Trash' Then compact all those pop mail account folders to remove all traces of marked as deleted emails. This should make your pop mail account empty and all old pop mail account emails safely stored in Local Folders. Now, if you want, you can remove the pop mail account via Account Settings. then perform a backup. Close Thunderbird. Copy and paste the 'Thunderbird' folder in this location to an external hardrive or suitable storage. C:\Users\<Windows user name>\AppData\Roaming\'''Thunderbird'''