Thunderbird Community Forum

I'm in the process of cleaning up Thunderbird e-mail before moving to a new computer. I started with 11,593 e-mails in my Inbox and 7,799 e-mails in my Sent folder. I'm now down to 7,634 in my Inbox and 4,965 in my Sent folder. I've allocated 2 weeks for this process and found that it's taking me about 3 hours per day to meet my daily goals. I'm finding that I'm spending at LEAST half the time responding to "Empty-Trash/Compact-folders" requests. There are times I can delete 50 e-mails at a time without getting a request. Other times I will try to delete ten e-mails and get the request. With the old version of Thunderbird I could literally delete hundreds of e-mails at a time. Can you help? Russ Bukwa Yardley, PA ps. I have intentionally given you specific numbers. Based on my software- and test-engineering experience, I speculate you need to create a stress test to solve this nagging problem.

Thunderbird 138/139, Windows 11 Pro 23H2. While composing a message, after a few lines the app freezes. Both the compose window and the main TB window freeze. Only opening the Windows Task manager allows me to close them. This did not happen with earlier versions.

If I save the message every few seconds while composing I can get most of the message back and continue after restarting TB. This behavior is the same in both the normal and troubleshooting TB modes. I can't even find a crash log to send to Mozilla.

Where shall I look next?

Thank you!

Can I use Thunderbird to build an incremental local backup/archive of all messages transiting (incoming/outgoing) a webmail account ?

Any idea how to achieve this ?

My problem is:

• A POP3 account will miss all folders except the Inbox. (It's a pity that POP4 has not gained traction yet.)
• An IMAP account creates a mirror, not a backup. Remote deletions in the webmail account must not delete messages from my backup and vice versa.

detailed requirements:

• one-way sync only, since a local backup/archive must be built, not a mirror (two-way synchronization):
• Remote deletions must not cause local deletions (otherwise it would be a mirror, not an archive/backup).
• Local move/delete operations must not be reflected back to the mail server.
• Read‐only access to the mail server: no moves, deletes or flags remotely.
• All messages in all folders must be included in the backup: Inbox, Sent, custom folders, etc. Since POP3 can only back up the Inbox, I will probably have to settle for IMAP to include all folders.
• No duplicates: Messages must not be stored locally more than once.
• Messages must be stored as full offline copies locally (not just headers).

I love Thunderbird, I think it is an excellent product all round, but one thing that really, really niggles me is that it continually marks certain senders as junk.

I receive Emails from these senders all the time, and often miss Emails because Thunderbird has marked them as junk, and moved them to the Junk folder, which means I don't see them on my mobile devices (IMAP).

I've marked this sender as "Not Junk" at least a thousand times. Each time it accepts my tag, and moves the Email back to the Inbox. However, that doesn't last, as the next Email, or the one after, or the one after that, ends up in Junk again.

I've seen a few posts that protest - this is not Thunderbird's fault, it's your Email provider, but I've already crossed that one off the list as I have white listed the entire domain at the Email provider. So nothing is getting flagged from the Email provider, to hint that it might be junk.

I'm always on the latest version of Thunderbird, and I have adaptive junk filter logging enabled, but it is completely empty of any logs. I also have "Do not automatically mark mail as junk if the sender is in "collected addresses" & "personal address book". I have a number of entries from this domain in the personal address book, as well as *.@domain-name.com, though I'm not sure if that format is correct to capture the entire domain.

Any help on this matter, gratefully received.

M

I have two issues that are related to a buggy interaction between Thunderbird and Microsoft's email server.

Issue (1) When I send an email with my Outlook email address (from the Android app or from outlook.live.com, but not Thunderbird), my email address shows up as a jumbled mess in the sent folder on Thunderbird.

It appears to the effect of

IMCEAEX-_O=FIRST+20ORGANIZATION_OU=EXCHANGE+20ADMINISTRATIVE+20GROUP+XXXXXXXXXXXXXXXXX+29_CN=RECIPIENTS_CN=XXXXXXXXXXXXXXXX@sct-XX-XX-XXXX-X-msonline-outlook-6f06c.templateTenant

(I have masked some potentially sensitive information).

In the sent folder on my Outlook Android app, my email address looks normal. It also looks fine on a browser in outlook.live.com. However, it's in the sent folder on Thunderbird that my email address is a mess.

Issue (2) When my Outlook email address is involved, the sending and receiving email addresses in the "correspondent" field are swapped in Thunderbird.

There are a couple situations where this swap happens:

1. Sending an email with my Outlook email account (either through the Android app or outlook.live.com, but not Thunderbird). In my Outlook sent folder on Thunderbird, the "correspondent" field shows my jumbled email address and not the receiving address, such as bob@gmail.com. Likewise, In the inbox of the receiving email account (such as bob@gmail.com) on Thunderbird, the "correspondent" field shows bob@gmail.com and not my Outlook email address.
2. Sending an email with any other account in Thunderbird to my Outlook email address. In my Outlook inbox on Thunderbird, the "correspondent" field shows my Outlook email address (this time unjumbled) and not the sending email address. However, in the sent folder of the sending email account in Thunderbird, the "correspondent" field shows up correctly (i.e., my Outlook email address).

These two issues are perplexing and probably related. Thank you for any help!

15.18.0 how to export to mobile from settings in the desktop thunderbird so i can use my android phone--if it will help, on my desktop there is no Export to mobile in settings!!!!!!!

hello I left account A (Google) and I am mainly using account B (Google) now. However, when I search for the mail of account A, it only shows the result, but after clicking it, it shows that there is no mail. How can I recover it? This is because the most important mail is in account A. PLEASE HELP ME....

I have set my account to "Don't delete any messages", because I frequently want to reread a deleted message in my Trash folder. However, when I go into my Trash folder to search for a deleted message, I am finding that messages older than a certain date have disappeared, although I've done nothing to permanently delete them. For example, today everything older than May 3 is gone. What can I do to prevent this?

thanks, CW

Hi there,

I've recently had a problem with a couple of client PCs where their Thunderbird profile folder has grown to fill the entire hard drive. In both cases, the relevant account folder in the profile's ImapMail dir had grown to over 300Gb. This account takes up 45Gb on the server (where I'm running Dovecot with maildir storage). In another case on both PCs, an 18Gb account had grown to over 90Gb.

Both client PCs are running up-to-date Thunderbird (139.0.2 64bit), one under Windows 10 and one under Windows 11. Both had auto-compact set, with the minimum saving reduced to 100Mb. Both problematic accounts are shared accounts that use a deeply-nested folder structure. In both cases, I was forced to delete and then recreate the these accounts in Thunderbird.

I'm an experienced sysadmin who is also running the mail server, so I am able to provide any extra info needed. Additionally, I accept that these are large email accounts; I'm in the process of setting up an email archive system for the client using Piler. I have read many other reports of outsize Thunderbird data folders; these are usually referring to less than 20Gb. The problems we're having seem to be an order of magnitude larger!

Thanks in advance, P.

I converted to Thunderbird 128,11.1esr in May 2025. My address book did not migrate to the newer version and I don't have the old one. Also, I don't know how to return to the previous version of Thunderbird.

I can only open my emails by right clicking it and opening in new window. Also keeps asking for password every time I go on Thunderbird. Have tried solutions on the help pages and online for both problems but not much use. Some things on account settings and security are not there to select. Is it correct that if I uninstall Thunderbird and then reinstall it the same problems will be present?

Will Thunderbird Release make it any easier to migrate Thunderbird from Win10 to Linux (Ubuntu or Mint)... With 200 million PCs becoming obsolete in a few months, I would think Mozilla would have noted that many of us are going to migrate to Linux but moving Thunderbird has been a nightmare (still unsuccessful nightmare). I've followed all the directives and none seem to work... I've been using TBird since it started and have a LOT of emails I'd prefer not to lose so if I could just get my Windows profile to work on Linux it would be great... I know you're busy, but we are facing an Armageddon of sorts out here... Help! Thanks a million cheers pj

We’re having a weird issue with Thunderbird that’s showing up on multiple computers using the same mailbox. When we search using the top search bar (Ctrl+K), it often doesn't find all emails that clearly match the search term For example, we have multiple sent emails with the searched phrase in the subject, but Ctrl+K only finds one of them, even though there are two (or more) that match. When we use Ctrl+Shift+F (advanced search) with the exact same keyword and folder, all the matching emails show up just fine.

So it's not like the emails are missing —they're just not being picked up by the Ctrl+K search.

The annoying part is that Ctrl+K lets us open the whole conversation thread, which is really useful, while Ctrl+Shift+F only shows single messages.

Ive tried to:

- repair folders

- delete .msf files

- rebuild global database

- reenable "Include messages in this folder in Global Search results" but it did not help

And this isn’t just one machine, it's happening on every PC where this mailbox is used

Tried all suggestions on re connecting thunderbird to gmail with no success. The new authorisation used by google is not working. I have thunderbird installed on Linux mint. Since i cannot use thunderbird i have moved to Evolution email client which has no problem at all connecting to gmail.

Since 5.18.2025 I get a "no message found" in my sent folders and other folders. "Find" will still find the messages and they can be opened, but I can't get the email folders to display. I know they are still there. Version 128.10.2esr. How can I get them to display in the folders?

I have a couple of hundred filters and one of them occasionally kicks in and unexpectedly moves certain messages to a new folder but I can't figure out which filter it is. Rather than me going through every filter manually, can't Thunderbird tell me which filter affected a given message? I'd like to be able to right-click a message and be shown the exact filter(s) which affected it.

Hello, I have a problem with one email account. Grouping does not affect it. It does not group... Everything was OK but I changed the POP server address to MAIL for a moment and then back to POP. Since then the account has not grouped. I want to have all the mailboxes "received" together. What could be the reason that this one account does not group and it used to group?

Mozilla's documentation on IMAP Synchronization Mozilla's documentation on IMAP Synchronization indicates

"Non-synchronized messages are still accessible within Thunderbird. The only difference is that rather than downloading the entire message, only the message "headers" are downloaded. (Message headers contain information like the sender, recipient(s), subject, etc - everything except the body of the message.) The message body is not downloaded until you click on the message in the message list"

Under what settings (e.g. Sync messages checked or unchecked) does this behavior apply?

Thanks.