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I recently added a email address to my thunderbird email and it brought forward a lot of messages from Yahoo that are spam. I would like to block them and instructions I have were dated 2016 from Mozilla. Is there a new instruction on how to block?

Hello Thunderbird Support, I am experiencing a severe IMAP folder synchronization loop with my Yahoo Mail account (paulpersonne519@yahoo.fr) inside Thunderbird. Yahoo Support claims the issue is caused by Thunderbird's folder mapping, so I am reaching out to you for a solution.

1. 1. The Problem:

The system-protected folder "Bulk" (Spam) has somehow been moved or mapped as a subfolder inside the "Trash" folder.

• In the Yahoo Mail Web UI (Chrome), the subfolder is invisible, but the Trash directory shows an arrow (^) indicating a child folder exists.
• In Thunderbird, the Bulk folder is clearly visible inside the Trash folder, marked with the flame (Junk) icon.

1. 1. What goes wrong:

When I delete spam messages via Thunderbird, they get trapped inside this nested Trash/Bulk directory. If I try to delete or empty it, the emails disappear but the folder itself cannot be removed.

1. 1. Steps tried so far that failed:

  1. Attempting to delete or rename the Bulk folder inside Trash gives the server error: [CANNOT] DELETE failed - Mailbox is reserved.
  2. Using Shift + Delete on the folder is rejected by the Yahoo server.
  3. Unsubscribing from the folder via "Advanced IMAP settings" -> "Show only subscribed folders" fails; Thunderbird re-downloads the structure on the next sync.
  4. I have completely deleted my old Thunderbird profile folder and created a brand new one using thunderbird.exe -P. Upon adding the Yahoo account via OAuth2, Thunderbird immediately pulled the same broken Trash/Bulk structure from the server again.

Since Yahoo refuses to help and claims Thunderbird caused this mapping loop, is there a hidden config setting (about:config) or a database override in Thunderbird that can force the server to release or move this reserved folder back to the root directory? Thank you for your assistance.

There was an earlier Case with the exact same name as what I named this case which was archived back in 2025. I have been living with this same problem since last year also. In the previous case there was reference to "downgrading" to an earlier version of TB, but there have been a bunch of updates since then so I doubt that would fix my problem because that earlier version is now over a year old.

I have one Gmail folder that correctly has one folder label "Junk." However, I have 4 folders that are AT&T related (2 from the domain "sbcglobal.net" and 2 from the "att.net.") For some reason when I set these folders up years ago they started out as labeled "Spam" instead of "Junk." Of those 4 folders 2 of them have the duplicated "Spam" folders, one from each domain."

When I go to Folder Properties I see "imap://XXXXX%40sbcglobal.net@imap.mail.att.net/Junk" on one of these Spam folders and "imap://XXXXX%40sbcglobal.net@imap.mail.att.net/Bulk" in the other. And the same "Bulk" vs "Junk" issue is in the other domain as well. All are named "Spam."

Can I simply delete one of these folders that are named "Spam" in each domain? Does it matter whether I delete the one ending in "Junk" or the one ending in "Bulk?"

Thanks.