Thunderbird Community Forum

Hello, I recently cleaned up my mail account and deleted obsolete folders on one device. The folder has been deleted on the server, but Thunderbird on another computer still shows the folder. In the subscribe menu the folder is not shown. But when I try to delete it it throws an error "The current command did not succeed. The mail server for account <account name> responded: [NONEXISTENT] unknown source folder.". The error makes sense since the folder has been deleted on the server. Is there a way to tell Thunderbird to just remove this folder?

Thanks in advance!

Today filtering of new emails fails for all folders. The message is "The message could not be filtered to folder <folder> because adding a message to it failed. Verify that the folder is displaying properly or try to repair it from the folder properties."

This is new. No problem filtering message a few days ago.

Windows 10 laptop PC.

Lots of free space on my local drive where Thunderbird is installed.

Where are these folders stored? I looked in C:\Program Files\Mozilla Thunderbird but I do not see any such folders there. I looked in C:\ProgramData\Mozilla but nothing there either.

Thank you.

I have a problem with Thunderbird on Kubuntu 24.04.3. The drag and drop of mails from inbox to TB-folders stop working after a while. It always happens when I minimize Thunderbird and maximize again, then the drag and drop has stopped working. I have also seen it if I for instance make a new folder, then it also stops working. It has been going on for a while now, at least the last 3 month. I have automatic update on, so I an running the latest version right now 140.4.0esr (64-bit).

I am using Thunderbird 115.5.2 (64-bit) on an older iMac on OS 10.12. I have four email address accounts, all gmail, and using POP. I have stored emails I wanted to keep in sub folders in Local Folders. This has all worked well for years.

Yesterday I lost lost all content from some of the subfolders in Local Folders, while some retained some content and a few seem intact. I also lost most emails that had arrived in the inboxes in the last week. The folder pane still shows the accounts, with their own set of folders. As usual, the inbox folders are highlighted with the number of new emails downloaded from the Gmail server to each address, but I can not see them in the message pane, or find them anywhere else. I sent a test message from one of my addresses to another – It didn't show as sent in Thunderbird, but did go through the gmail server and the message count of downloaded messages on the recipient address went up by one, but I couldn't see the email. Then I tried clicking on the folder "properties" then 'Repair Folder' but nothing happened, although the information on that window showed the number of messages and MB that I would expect to be in that folder, rather than what was there, which presumably means they may still be in there somewhere? I would be very grateful for help – I'm not tech savvy and feeling completely lost.

"Could not get folder db" is the message. I've tried all the suggestions that google provided - nada

Windows 11 25H2 (OS Build 26220.7271) Thunderbird 145.0 (64-bit)

5 accounts are defined. Some filters work on startup, but new ones do not. Manually running filter results in "could not get folder db"

Hi,

we use Thunderbird for several business e‑mail accounts (for example info@… and similar), all configured as IMAP, and the same mailboxes are used by multiple people on several computers. Our mail server hostname is nickel.studio4web (Studio4web hosting).

We have noticed the following strange behaviour of messages (usually customer orders):

A new message arrives normally in the “Inbox” folder.

After some time, for example the next day, the same message also appears in the “Trash” folder, but it is still visible in “Inbox” at the same time.

We checked the headers; the Message‑ID field is exactly the same in both Inbox and Trash, so it looks like one and the same mail that exists in two folders at once.

In Thunderbird Server Settings we configured the delete behaviour so that messages are either moved to Trash or removed immediately (we tested both options), and after that we ran Compact on both the Inbox and Trash folders. However, some messages still remain simultaneously in Inbox and Trash.

We know that other team members open the same accounts in other clients / on mobile phones or in webmail, but we are not sure whether that alone can explain this double appearance of the same message (Inbox + Trash).

For example, two order emails from 03.12. were in Inbox only on that day, and today we see them also in Trash, while they are still in Inbox. No one remembers explicitly deleting them.

Questions:

Is this behaviour normal for IMAP in Thunderbird, or does it indicate some bug or wrong configuration?

Is there a way to prevent a single message from being present in both “Inbox” and “Trash” at the same time (so that it is either only in Inbox or only in Trash)?

What else should we check in Thunderbird settings or on the mail server (filters, special IMAP options, automatic cleanup, server‑side rules, etc.) to avoid such “duplicate” messages?

Environment:

Thunderbird version: 140.5.0esr

Operating system: Windows 11 Pro

Mail server / provider: nickel.studio4web (Studio4web hosting)

Thanks in advance for any help and advice.

Good afternoon, I am using Thunderbird for many years now. In the last ~2 years I have seen several times the subfolders of the mail folder disappearing from the list on the left panel. All of them are correctly subscribed. I would like to know if there exists a way to recover them different from deleting the account and recreating it. I am currently running Windows 11 Pro 25 H2 with Thunderbird 145.0.

Did anyone experienced such an issue? Thanks Riccardo