Thunderbird duplicates folders
I am using Thunderbird 128.4.2esr (64-bit) with IMAP where all mails are moved to a folder structure in the local folder.
Since the latest updates of TB, I see that some of my folders under "local folder" suddenly become doubled like
Inbox/FolderA Inbox/FolderA-1
The original FolderA contains sub-folders and even sub-sub-folders. The newly generated FolderA-1 seems to contain all messages from the original folder, but just plain without the sub-folder structure.
It seems that the new FolderA-1 was generated as a kind of backup. It is hard to decide if this new folder can be deleted. The AddOn "Remove Duplicate Messages" does not work here, since it only works on a single folder. Moving all messages from the new folder into the original one does not help either, since the AddOn does not compare messages between folders and their sub-folders.
How can these problems be handled?
Alla svar (2)
Generally, when a folder on PC is doubled, it is indicating that thunderbird was unable to close the file on last termination. That could be an antivirus or other software interfering or that the folder somehow got marked read-only. You may find that the new folder has the same content as the old folder. You can fix this by exiting thunderbird and use windows file explorer to delete the unwanted copy. But I always make copies before deleting.
I had this case a few times now with partly some 100 messages in such folders. Manually checking if a message is missing is too time consuming.
The question remains how this could be handled.