Thunderbird Community Forum

Dear Thunderbird Team,

I am writing to report a critical issue with the Thunderbird Extension API where it returns stale, cached data instead of live folder contents for Gmail IMAP accounts.

Issue Description The browser.messages.list() and browser.messages.query() APIs are returning outdated message data from 2016-2021, completely ignoring the actual current contents of my Gmail IMAP inbox. While Thunderbird's UI displays current emails correctly, the extension API serves permanently cached old data.

Evidence of the Bug What Thunderbird UI Shows: Current inbox with emails from today and recent weeks

Real-time folder contents

Proper folder synchronization

What Extension API Returns: Only 100 messages total (artificial limit)

Messages exclusively from 2016-2021

No emails from 2022-2025 present

Completely ignores current folder contents

Technical Details: Profile: /Volumes/Data/Mail Files/Thunderbird/Profiles/aq8q4la7.default-release/

Account: Gmail IMAP (imap.googlemail.com)

Folder: account1://INBOX

API Used: browser.messages.list(folderId) and browser.messages.query()

Steps to Reproduce Set up Gmail IMAP account in Thunderbird

Write extension using browser.messages.list() API

Compare API results with actual folder contents

Observe API returns stale cached data from years ago

Debugging Attempted We have tried:

Deleting all .msf index files

Clearing folderCache.json and global-messages-db.sqlite

Removing cache folders (cache/, cache2/, startupCache/)

Rebuilding folder indexes

Using different API methods (messages.query vs messages.list)

None of these resolved the issue - the API continues to return the same stale dataset.

Impact This completely breaks any extension that needs to access current folder contents, such as email tracking, automation, or filtering extensions.

Request Please investigate why the Extension API serves different (and outdated) data compared to Thunderbird's main UI, and fix the API to return actual live folder contents.

Thank you for your attention to this critical issue.

Best regards, Hasan

Hi I was using TB 142 without problems. When upgrading to 143 ou 144.B4 I have problems sending mails to all users after some times. Usually the first mails are sent immediatly but after around 10 mails, I have very slow response (varies from 5 sec to more than 1 minute and sometimes timeout). Usually quitting TB solves the problem but this is very annoying. I went back to 140LTS and sems to have no longer this problem. This was tested on many diffrent networks. I am running under Fedora release 42

Thanks

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Can you please help me so I can successfully back-up all my inbox messages? Once I figure out an approach want to continue backing up messages using this approach.

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Hello all!

I use Thunderbird as a local archive for my email. I have two accounts in the application: my home email via my ISP (POP) which I predominately use and my gmail (IMAP) which I don't generally use. There are years of messages in folders and sub-folder under the POP account, but nothing under the IMAP.

I’m up to date with Thunderbird at v140.1.0esr (aarch64) on my iMac with Sequoia 15.8.

On 07/22/2025 I went to download some messages via my ISP POP account and saw that a whole bunch of my email folders no longer had any subfolders and were empty of any messages. Some were also duplicated. Please see the attached image.

I haven’t changed any settings in years, and I do not have any add-ins. One of the nice things about Thunderbird has been its solidity and simplicity.

After every session, I would empty my trash and compact.

Suddenly my email seems to be gone along with sub-folders while top level folders are duplicated.

Wondering if anyone has any suggestions on how to troubleshoot this? Since I don't do anything fancy with the application and with the suddenness of this issue, I can't image I'm the only person having it? I’m quite concerned I may lose many years’ worth of messages.

Thanks much in advance! CPRoot

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