Thunderbird does not create 'spam' folders because by default it uses 'Junk' and only for POP accounts. It sounds like you are using IMAP because 'Spam' is a folder name used on server/webmail accounts. This means you are subscribed to see them. It is likely the one with capital S is the default server folder. Make sure the imap account is set up to use the 'Spam' folder. * Account Settings > Junk Settings * select 'Move new mesages to' * Select 'Other' * Choose the 'Spam folder on account name' Then 'unsubscribe' from seeing the 'spam' folder from Folder Pane. Right click on imap account name folder in Folder Pane and select 'Subscribe' Select the 'spam' folder and click on 'Unsubscribe' Logon to webmail account via a browser and then delete the 'spam' folder.