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Request Please investigate why the Extension API serves different (and outdated) data compared to Thunderbird's main UI, and fix the API to return actual live folder contents.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

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Good morning, after the 143 update the Send Later add on is marked as not compatible, but I see now that also with 143.01 It persist and that the version 10.7.2 should be compatible but TB does not want to install it, no matter what citing "is not compatible". i tried all suggestions from the developer (the add is compatible to 144) but to no avail. He thinks this is an issue with TB.

Can you please help ?

Kind regards