Thunderbird Community Forum

I keep my mail (both sent and received) in local mail folders. My server is gmail, and sent mail is put in gmail's sent folder by default. Every few months, I copy those messages to a local folder, and after I back them up, I delete the server copy.

What to my dismay, I discovered today that only the message headers, and not the messages were present in the local folder, though they had been when downloaded. Looking at the file sizes, I found the sent file to be 0 Kb, and sent.msf 255 Kb, when sent should have been around 60 Kb long.

I have been able to restore the messages from backup (whew!), but I have no idea how then sent file was wiped out. I know I did not do it.

Has anyone else had this happen? Is there a preventive measure I should take?

Hello,

I am on Thunderbird 150.0.2 for Windows.

I am really suffering here. I need to change the font weight of unread messages. In a non-threaded list.

The default weight I get with my preferred font (Trebuchet MS) is not bold. It is BLACK. When I say BLACK, I mean ultra bold, display font, heading weight. Heavier than the boldest font that even exists in the font family. Thunderbird is creating this ultra mega black font by taking the bold font variant and applying a faux bold effect to it. The result is that the text is so heavy that it takes up twice as much horizontal space as the ordinary bold font variant. This becomes a usability issue because it's not possible to see the date, sender, and subject at the same time.

I have struggled and strived with userchrome.css. Spent hours combing through forums here and elsewhere. I've already enabled the mystery setting in the config editor. I put userchrome.css where it is supposed to be.

I saw a blog post from Mozilla that says "userchrome.css is not supported". What is the actual meaning of this? That it has been actively blocked from working anymore, ever, for anyone? Or that users are taking risks if they create userchrome.css? Why can't developers speak plain language? "Not supported" could mean many things.

When I go to the Style Editor, userchrome.css does not exist there. Which leads me to believe that user customizations are absolutely deprecated and we are not permitted to use userchrome.css.

I tried editing some of the rules in the Style Editor, but could not determine any way of actually storing the changes. When I click Save, I get a dialog where I can **EXPORT** the file. But I can't seem to actually save the changes, because CSS files do not appear to exist in the installation directory. It must be compiled into some library.

This is extremely unsatisfying and super frustrating. Just getting straight answers to things is super difficult, nothing stays the same for more than a couple months, and up to date information either does not exist or is not found by any search engine.

So, please help. I just need to change one setting, the font weight of unread messages. Since Thunderbird is allegedly open source, I thought I would have some ability to make such changes. But the Style Editor doesn't seem to actually be an editor, but merely a read-only interface to precompiled rules? If I wanted to change the font weight of unread messages, would I be forced to compile my own version of Thunderbird? I'm not competent to do that, and it would probably either prevent updates, or the updates would break my changes.

Please help, I am super desperate. I need to see the date, sender, and subject all at the same time. That doesn't seem like an unreasonable ask.

I would gladly pay for an email client that gives me control over my data *and* allows me to control the UI, but apparently that doesn't exist.

After I migrated everything to a different computer, 'Local folders' no longer appears in the side bar, so I cannot archive messages locally.

Can some kind person please help me to reinstate it?

I was cleaning up my Inbox when I looked at the "Important" folder. I read in a number of places that this is a "Gmail" thing, and messages get in this folder apart from any action etc on my part.

I have a couple questions.

FIRST, are the emails in the "Important" folder only in that folder or are copies in there? I deleted a number of 2 to 3 year old emails that I do not consider important today. The closer I get to this year [2025], the more careful I get.

SECOND, how can the auto-population of that folder be stopped and the folder be deleted? I keep my important emails in designated folders so I can find them.

Thanks in advance

I've been running TB for 10-12 years, generally with no problems. When I logged in on 5/13/26, I saw that Windows had run an overnight update:

    2026-05 Security Update (KB5089549) (26200.8457)

Thunderbird (version 147.0.2.0) was not running, although it had been when I slept the PC the previous night.

Now, when I try to start TB it gives me the crash report dialog. Selecting the Restart option just brings me back to the crash report.

In searching for possible causes, I see that this may be caused by a bad profile. So I open the profile folder with (run) %APPDATA%\Thunderbird\Profiles\ which in my case is:

  C:\Users\<user_name>\AppData\Roaming\Thunderbird\Profiles

This is an empty directory. But if I go up one level to \Thunderbird there is a profile.ini file which contains (actual user ID replaced by <user_ID>:

[Install8216C80C92C4E828] Default=E:\Thunderbird\Profiles

[Profile0] Name=<user_ID> IsRelative=0 Path=E:\Thunderbird\Profiles Default=1

[General] StartWithLastProfile=1 Version=2

"E:\Thunderbird\" is the correct location of my TB installation. In that directory is a profile.ini file that contains:

[General] StartWithLastProfile=1

[Profile0] Name=default IsRelative=1 Path=Profiles/<user_ID>.default

Directory "E:\Thunderbird\Profiles\<user_ID>.default" is present. But all of it's files are dated 2010 except Mail, dated 2016.

Directory "E:\Thunderbird\Profiles" contains the ImapMail and Mail sub directories totaling about 25GB data.

I don't know what the Thunderbird startup process is or if this all looks correct. Can someone give me a sanity check? If this looks normal, what else could be corrupted?

Thanks in advance.

Ever since the latest update, when I hit send for an email. It says it cannot send, I cancel, hit send again and it goes through. I have to try sending EVERY email twice.

I have been using Thunderbird with two POP3 Hotmail accounts for some time and I am trying to set up a third account with exactly the same configuration. However, both the automatic and the manual configurations failed. The new account receives mail, but the outgoing smtp server config seems to have a problem. Sending messages times out or keeps prompting for a new password.

The Hotmail account has POP3 and IMAP enabled. Thunderbird is set to receive all cookies. I cleared history and cache after every attempt and also temporarily disabled the firewall.

Any suggestions about what the problem could be?

Recently, I have experienced an erroneous browser launch, simply by clicking on the title of the message in the list pane. This problem seems to occur when clicking on emails from a particular UK supermarket (tesco.com) and the web page opened has a long and complicated URL, but the page contains only a single pixel which shows up as a white dot on a black background.

Obviously, it is likely that there is something strange about that source, but the problem doesn't occur if I click on the same email in a different email client (in this case Evolution).

I have tried various Settings as advised by web searches and also the solutions suggested in Thunderbird Help (Troubleshooting Mode and Troubleshooting Information).

I am running Thunderbird 140.5.0esr (64-bit) on Kubuntu Linux 24.04.

I just installed a new router and all of a sudden nothing is working properly on my PC. Among other things, I need to fix Thunderbird, and for that I need to find where my thunderbird profile is. The instructions I've seen say to go to troubleshooting information, find profile folder, and click on "open folder." When I do that, nothing happens. (I told you installing the router appears to have broken everything--I don't know how that happened, especially since I was on the phone with tech support for the router for install), and I'm no closer to finding the profile file. I can enter %appdata%\roaming\thunderbird\profiles but that shows me two different profile directories and I don't know which one is the right one. How can I find the correct file and why doesn't troubleshooting information just show me that?

This only recently started happening. This has been tested on 3 different computers. Windows 10 Pro on all three.

With VPN on: Bluemail works fine.

Thunderbird can connect and download messages, but when I try to send a message, it gives an error.

With VPN off:

Bluemail and Thunderbird both work fine.

Hello (this might fit better in "performance & connectivity?): Tbird 140.10.1 & .2 esr. W11p laptop v23. As of tonite (15may26), after update from 140.10.1 to .2, in a message, the "buttons" for a web link no longer appear, in the msg body. Instead the link is shown in full. How can I fix that?

Here's an example (others are longer) from our local rag "Press Democrat."

Header Logo <https://enews.nl.pressdemocrat.com/q/ qH1rRJrBKJ0Xyf9LNp1wEwHDTif8o4tQ5y1ZcOJcHNsZGRhQGdtYWlsLmNvbcOIyz_GZ83be6bPLq- ZFHTNYUc43xg>

I also closed & re-opened tbird, did NOT reboot laptop. Problem remains.

Thank you.

Email will not send. Message-- "Sending of the message failed. An error occurred while sending mail. The mail server responded: Email rejected. Please verify that your email address is correct in your account settings and try again." I am not sending to another person but testing with my personal email. Thank you.

Drgan Maric, 74, Belgrade, Serbia. This is my self-taught English.

I use Thunderbirad for years, including small donation when I start to use it. Since a few days I can not open WebMail from cPanel of Namecheap,

Nothing is changed in both servers and ports. In Account Settings Outgoing Server has an option to TEST connection for server. Result failed.

An Attachment is an immage of TEST and RESULT FILED.

In this age, with broken spine and almost immovanle, it makes me very frustrated. Coud you plase reaolve this issue and make Thunderbird to work properly and peace in my mind,

How do I change Thunderbird's icon back to the older version? The new version looks a lot like Signal's icon. When I have a taskbar full of icons, I have to look carefully to make sure I'm selecting the correct icon for the app I want to switch to. It's annoying. Thanks

Hi all,

I'm desperately hoping someone can help me fix this so I don't have to dump Thunderbird for a different email client.

I have an email account hosted by some hosting company on a domain I own.

I noticed that Thunderbird was not returning certain emails when I searched for them. I searched, and found articles telling me to rebuild GloDa, so I followed the instructions to do that and quit Thunderbird and deleted the file. When I re-opened Thunderbird it started the re-indexing process, which I was viewing in the Activity Manager tool.

... except it only indexed a couple of the folders in my email account. It didn't index my archives, trash, spam, etc. It basically only archived the inbox and sent folders. I can see that from the list of completed tasks in the Activity Manager.

I've read on Mozilla's pages that Thunderbird indexes all folders, but it did not in my case, and as a result search is only returning a tiny proportion of my emails.

I need to be able to accurately track communications with my customers, so obviously if I can't get this fixed I'll have to move to a different email client.

I would greatly appreciate any help anyone can provide.

Ich erhalte die Meldung "Nachrichten konnten nicht in die Mailbox-Datei geschrieben werden. Stellen Sie sicher, dass das Dateisystem Ihnen Schreibrechte einräumt und genügend Speicherplatz zur Verfügung steht, um die Mailbox zu kopieren." Speicherplatz ist genügend vorhanden. Bis jetzt konnte ich meine Emails problemlos abholen. Bin erreichbar über Telefon [edited] oder Handy [edited phone#'s from community support forum]

We have bought a new computer from our tech guy before. This time, all was fine except for the Thunderbid calendar. The 20 GB of email files are all there and email still works. Only the calendar is blank. Our guy admits he dislikes Mozilla and rarely deals with it. Is there any way we can find the contents of the calendar? The old computer is still here in our house, but we only have one monitor. I had birthdays, lots of birthdays setup as repeating events. I hate to lose that.

This is odd as we didn't lose anything the last time we bought a new computer from same guy. We already were running Windows 11, so that is not the issue.