If the original account in thunderbird was an IMAP account and the IT guy changed only the server settings, so it is still using same email address but now points to a different server - note - Imap mail accounts show a virtual copy of what is on the server, so if the account is now pointing to a new empty server then that is precisiely what you will see. All folders and emails were stored on the original server. Before changing the server settings to point to another empty server, the IT guy should have done one of the following: Synchronise the folders for offline to get full copies downloaded and then put copies of all folders and emails into Thunderbird 'Local Folders' mail account, so you would have a copy of emails on your computer. This would mean you could put them back onto the new server at a later time. OR all account email and folders should have been migrated from old server to new server, so that when the imap mail account settings were changed to point to new server, all your old folders would on that new server. If the latter is the case, then they should be visible when accessing the webmail account via a browser. In Thunderbird try subscribing to see server folders. Right click on imap mail account name in Folder Pane and select 'Subscribe'. Select folder names and click on 'Subscribe', click on 'OK'. re :''A few days after that, when I open Thunderbird now, it started opening on the page for the account, the one with the menus for email, accounts, and advanced features. '' If you selected the mail account name in the left Folder Pane prior to closing Thunderbird then next time you start Thunderbird, it will open showing exactly as you describe. But if you subsquently select the Inbox and close, upon restart it should open on the Inbox.