Menu app icon > Help > More TRoubleshooting Information Under 'Application Basics' - Profile Folder ' click on 'Open Folder'

a new window opens showing contents of profile name folder.

Exit Thunderbird now.

Click on ImapMail folder Click on imap mail account name folder

This will display all your mbox files (no extension - they contain emails) and their index files (*.msf extension - no emails). This is where the 'Bulk'Mail' mbox file and 'Bulk Mail.msf' file should be located. In the same location as the 'Inbox', 'Drafts' etc

However, it got moved by accident, but I'm guessing the server probably did not trash it as it is a default folder. click on 'Trash.sbd' folder You should see the 'Bulk'Mail' mbox file and possibly the 'Bulk Mail.msf' file. Move them out of the 'Trash.sbd' folder and put them back in same place as the 'Inbox', 'Drafts', 'Sent' etc

Usually you cannot simply move folders and expect them to appear in an imap account because upon start up the first thing that is checked is the folder and whether they exist etc. But I'm thinking the server should not put Bulk Mail in Trash and therefore expects it in the normal location. So try this first.

Start Thunderbird.

I'm sorry but this didn't work. I also tried removing the email account and reimporting it and that didn't work

UPDATE. Follow same instructions as before to access profile folder - remember to exit Thunderbird - but this time delete the 'Bulk'Mail' mbox file and 'Bulk Mail.msf' file. Also delete the 'Trash.sbd' folder

Do Not restart Thunderbird

Logon to the webmail account via browser. Where is the Bulk Mail Folder ? Is it in the webmail Trash folder? If yes, try moving out.

I updated previous comment please make sure you use the updated comment.

I've had this problem for months, and had found the same solution Toad-Hall 1st outlined above on a different website which didn't work back then. The issue has been discussed recently in ATT mail support and Reddit's Thunderbird thread, but no one has come up with a solution yet.

Searching Mozilla support landed me here, and I've tried Toad-Hall's modified post from May 23, 2022 deleting 'Bulk Mail' mbox file, 'Bulk Mail.msf' file, and 'Trash.sbd' folder. At that point I checked my Yahoo mail via a browser where the Trash and Bulk folders have never been nested, and found them separate as usual.

But then when I went ahead and launched Thunderbird, the Bulk folder was automatically moved into the Trash folder both within Thunderbird and in the Windows \AppData\Roaming\Thunderbird\Profiles\a7ankggz.default\ImapMail\ folder.

This is only an issue on one of several of my Yahoo Mail accounts. And I'm seeing the same Bulk folder nested in Trash in the same account on both my Windows PC and Windows notebook installations of Thunderbird.

The issue isn't resolved by installing a fresh copy of Thunderbird.

TRy:

• Right click on imap mail account and select 'Subscribe'
• Select 'Refresh'
• Select 'Bulk Mail'
• click on 'Unsubscribe'
• click on OK.

Now to see if the cache folders are interfering.

• Menu app icon > Help > More TRoubleshooting Information
• Under 'Application Basics' - Profile Folder ' click on 'Open Folder'

a new window opens showing contents of profile name folder.

• Exit Thunderbird now.

• Click on ImapMail folder
• Click on imap mail account name folder
• click on 'Trash.sbd'
• Move the 'Bulk Mail' mbox file, 'Bulk Mail.msf' file out of 'Trash.sbd' back up to same location as 'Inbox', Drafts etc.
• Delete: 'Trash.sbd' folder.
• Delete 'Trash.msf'

DO NOT start Thunderbird.

Access this location: C:Users/User Name/Appdata/Local/Thunderbird/Profiles folder It is important that you are looking in the Appdata/ 'Local' folder. Delete the profile name folder. You could use the info in the image below as a quick way to access that location.

DO NOT start Thunderbird. You say you have this problem on PC and Laptop re: I'm seeing the same Bulk folder nested in Trash in the same account on both my Windows PC and Windows notebook

Logon to the other computer and repeat exactly the same as above. Then restart Thunderbird.

Well I've done this enough to have the general process memorized at this point. 'Subscribe', 'Refresh', Select 'Bulk Mail', 'Unsubscribe', click on OK. is a new twist along with deleting (renaming to -bak) the \Local folder.

But unfortunately no joy. Backed up the copy on the desktop, and followed your instructions, then restarted it before going the 2 system route. Then repeated the whole process on both systems before starting TBird on them again. Same results with Bulk being moved back into Trash.

Of the numerous email accounts I've got configured in TBird, this one is the oldest, and it's very, very old with a lot of mail and a lot of sub-folders I've been filtering incoming mail into. I can't help but wonder it this might be a problem at the server end at this point.