Right-click on the account name in the left pane and choose "Subscribe", then click the "Refresh" button. That should clean up the folder list.

Right-click on the account name in the left pane and choose "Subscribe", then click the "Refresh" button. That should clean up the folder list.

I followed your instructions and I see the folders in the list where I can subscribe. I subscribed to the folders that I wanted to see and all the parent folders, but I still don't see the missing folders in the left pane.

Are you saying the old folder names disappeared but the new ones still don't show?

How about this? There's feature called "Folder Modes", one of which, "Recent" may hide folders that only contain older messages. Could one of those modes be enabled? I quote from this article:

https://support.mozilla.org/en-US/kb/switching-folder-pane-view

"There are several "views" that can be used to display in the folder pane. The view you select will determine how the folders are organized and displayed (while not affecting the actual folders or messages themselves.) Select View > Folders from the menu bar, or select Folders from the application menu, to choose the view you want to use. The following options are available:

• All: This is the default view shown above. It shows each email account and its folders.

• Unified: This view combines the messages in all of your accounts into similar folders. In this view, your Inbox (and Archives, and Trash, etc) will contain the messages from all of your Inboxes in all of your accounts.

• Unread: This view only shows account and folders that contain unread messages.

• Favorite: You can make a folder a "Favorite" by selecting Edit > Favorite Folder from the menu bar, or by selecting Folders > Favorite Folder from the application menu, or by right-clicking on the folder name and selecting Favorite Folder. When you select the Favorite view, only those folders that you have specified as favorite will be displayed.

• Recent: This view will display any folders that have had activity in the last 15 days.

Thanks for the suggestion.

I have "All Folders" selected. I tried selecting the others, but the views that were created did not show the missing folders.

Two thoughts...

- Go to Menu item: Tools | Account Settings | Server Settings | "Advanced" button

Is the "Server supports folders that contain sub-folders and messages" enabled?

I found this possible solution to "phantom folders" on Reddit. I have not tried it. Worth a shot, maybe?

https://www.reddit.com/r/Thunderbird/comments/qhzdcv/comment/mmpkse6/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

- Go to Tools | Account Settings | Server Settings | "Advanced" button

- Uncheck the "Show only subscribed folders" option.

- Restart Thunderbird. All folders may disappear from view (but they're still there on the server!)

- Go back to the same Advanced options and CHECK "Show only subscribed folders".

- Restart Thunderbird again.

Hopefully your new folders will show. If your old folders also show, they should now be deletable.

I found this possible solution to "phantom folders" on Reddit. I have not tried it. Worth a shot, maybe? https://www.reddit.com/r/Thunderbird/comments/qhzdcv/comment/mmpkse6/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button - Go to Tools | Account Settings | Server Settings | "Advanced" button - Uncheck the "Show only subscribed folders" option. - Restart Thunderbird. All folders may disappear from view (but they're still there on the server!) - Go back to the same Advanced options and CHECK "Show only subscribed folders". - Restart Thunderbird again. Hopefully your new folders will show. If your old folders also show, they should now be deletable.

This seems to have solved the problem. Thanks.