See https://support.mozilla.org/en-US/questions/1360261

Thanks sfhowes but it does not work. i have 3 files: prefs-1.js, prefs-2.js and prefs-3.js all empty (0 kb). Instead, I entered my data in the setup opening window ofThunderbird. Now I can see the remote directories on my server (I can connect to server) but not my folderstructure under "Local folders". The file prefs.js now contains the following lines:

user_pref("mail.account.account1.identities", "id1"); user_pref("mail.account.account1.server", "server1"); user_pref("mail.account.account2.server", "server2"); user_pref("mail.account.lastKey", 2); user_pref("mail.accountmanager.accounts", "account1,account2"); user_pref("mail.accountmanager.defaultaccount", "account1"); user_pref("mail.accountmanager.localfoldersserver", "server2"); user_pref("mail.folder.views.version", 1); user_pref("mail.identity.id1.archive_folder", "mailbox://claudia.florian%40rdsmail.ro@pop3.rdsmail.ro/Archives"); user_pref("mail.identity.id1.doBcc", false); user_pref("mail.identity.id1.draft_folder", "mailbox://claudia.florian%40rdsmail.ro@pop3.rdsmail.ro/Drafts"); user_pref("mail.identity.id1.drafts_folder_picker_mode", "0"); user_pref("mail.identity.id1.fcc_folder", "mailbox://claudia.florian%40rdsmail.ro@pop3.rdsmail.ro/Sent"); user_pref("mail.identity.id1.fcc_folder_picker_mode", "0"); user_pref("mail.identity.id1.fullName", "Claudia Florian"); user_pref("mail.identity.id1.reply_on_top", 1); user_pref("mail.identity.id1.smtpServer", "smtp1"); user_pref("mail.identity.id1.stationery_folder", "mailbox://claudia.florian%40rdsmail.ro@pop3.rdsmail.ro/Templates"); user_pref("mail.identity.id1.tmpl_folder_picker_mode", "0"); user_pref("mail.identity.id1.useremail", "claudia.florian@rdsmail.ro"); user_pref("mail.identity.id1.valid", true); user_pref("mail.openMessageBehavior.version", 1); user_pref("mail.purge_threshhold_mb", 20); user_pref("mail.purge_threshold_migrated", true); user_pref("mail.rights.version", 1); user_pref("mail.root.none", "C:\\Users\\Claudia_F\\AppData\\Roaming\\Thunderbird\\Profiles\\n69eeboc.default\\Mail"); user_pref("mail.root.none-rel", "[ProfD]Mail"); user_pref("mail.root.pop3", "C:\\Users\\Claudia_F\\AppData\\Roaming\\Thunderbird\\Profiles\\n69eeboc.default\\Mail"); user_pref("mail.root.pop3-rel", "[ProfD]Mail"); user_pref("mail.server.server1.check_new_mail", true); user_pref("mail.server.server1.clientid", "5380250d-4989-4553-abc8-94e9d2226ac6"); user_pref("mail.server.server1.delete_by_age_from_server", true); user_pref("mail.server.server1.delete_mail_left_on_server", true); user_pref("mail.server.server1.directory", "C:\\Users\\Claudia_F\\AppData\\Roaming\\Thunderbird\\Profiles\\n69eeboc.default\\Mail\\pop3.rdsmail-1.ro"); user_pref("mail.server.server1.directory-rel", "[ProfD]Mail/pop3.rdsmail-1.ro"); user_pref("mail.server.server1.download_on_biff", true); user_pref("mail.server.server1.hostname", "pop3.rdsmail.ro"); user_pref("mail.server.server1.lastFilterTime", 27950047); user_pref("mail.server.server1.leave_on_server", true); user_pref("mail.server.server1.login_at_startup", true); user_pref("mail.server.server1.name", "claudia.florian@rdsmail.ro"); user_pref("mail.server.server1.nextFilterTime", 27950057); user_pref("mail.server.server1.num_days_to_leave_on_server", 14); user_pref("mail.server.server1.port", 110); user_pref("mail.server.server1.socketType", 0); user_pref("mail.server.server1.spamActionTargetAccount", "mailbox://claudia.florian%40rdsmail.ro@pop3.rdsmail.ro"); user_pref("mail.server.server1.storeContractID", "@mozilla.org/msgstore/berkeleystore;1"); user_pref("mail.server.server1.type", "pop3"); user_pref("mail.server.server1.userName", "claudia.florian@rdsmail.ro"); user_pref("mail.server.server2.directory", "C:\\Users\\Claudia_F\\AppData\\Roaming\\Thunderbird\\Profiles\\n69eeboc.default\\Mail\\Local Folders-1"); user_pref("mail.server.server2.directory-rel", "[ProfD]Mail/Local Folders-1"); user_pref("mail.server.server2.hostname", "Local Folders"); user_pref("mail.server.server2.lastFilterTime", 27950047); user_pref("mail.server.server2.name", "Local Folders"); user_pref("mail.server.server2.nextFilterTime", 27950057); user_pref("mail.server.server2.spamActionTargetAccount", "mailbox://nobody@Local%20Folders"); user_pref("mail.server.server2.storeContractID", "@mozilla.org/msgstore/berkeleystore;1"); user_pref("mail.server.server2.type", "none"); user_pref("mail.server.server2.userName", "nobody"); user_pref("mail.smtp.defaultserver", "smtp1"); user_pref("mail.smtpserver.smtp1.authMethod", 3); user_pref("mail.smtpserver.smtp1.clientid", "59c0b570-34b8-4562-bae8-edca43397389"); user_pref("mail.smtpserver.smtp1.description", "claudia.florian@rdsmail.ro"); user_pref("mail.smtpserver.smtp1.hostname", "smtp-rdsmail.rcs-rds.ro"); user_pref("mail.smtpserver.smtp1.port", 465); user_pref("mail.smtpserver.smtp1.try_ssl", 3); user_pref("mail.smtpserver.smtp1.username", "claudia.florian@rdsmail.ro"); user_pref("mail.smtpservers", "smtp1"); user_pref("mail.spam.version", 1); user_pref("mail.startup.enabledMailCheckOnce", true);

The prefs.js shows that Local Folders are stored in ...Mail/Local Folders-1. Open Account Settings, select Local Folders in the left pane, then Browse... in the right pane to ...Mail/Local Folders, then restart TB and see if Local Folders in the Folder Pane appear as before. The same method can be used if a POP account is now pointing to Mail/pop3.rdsmail-1.ro when the previous location was Mail/pop3.rdsmail.ro.

It worked all right!!! Many thanks. Now I have 2 trees starting from 2 Local folders. May I ask why?

The folders with -1 in the name are created when TB loses track of the profile. If you wish to clean up the Local Folders display, it's possible to move messages into a single location, but be careful to not lose anything.