Spontaneous appearance of new folders among Local Folders: Another Thunderbird user, a member of our computer club, has experienced a strange event in his TB folder structure. He regularly saves incoming emails to his Local Folders (from one or other of two IMAP accounts). Recently he has found that new folders have appeared spontaneously among his Local Folders, usually bearing the name of an existing folder with name suffixed with "- 1" then "- 2", as in "<oldname> - 1". One folder seemed to be a copy of an old folder including most of its contents; others have had only one, or no contents. Host OS is Windows 10. Our member has Version 128 of TB with automatic updating. We have replaced his Profile (by renaming the old Profile) but the problem has returned. At the return one of the new folders has a name of this form: "<Personal name of friend>.msf.compact - backup". Has anyone else seen this behaviour? What might be the cause? Do we need to uninstall and reinstall Thunderbird to cure this sickness? (Our computer club is Melbourne PC User Group, Australia.)