Thunderbird Community Forum

As of a few days ago, when I open Thunderbird, various unprecedented and unpleasant things happen. Sometimes I immediately get a message that my account is "processing," and that I need to wait a while before accessing messages. More annoyingly, though, often when I do start downloading new messages, it downloads a few but then freezes. (I can see how many there are, e.g. "Downloading 5 of 48 messages," but then it freezes at 5.). After another minute or so (not sure about the exact timing), Thunderbird goes into "not responding" mode, and my only option is to close the program; rinse and repeat. Sometimes I will get this message: "Unable to write the email to the mailbox. Make sure the file system allows you write privileges, and you have enough disk space to copy the mail." (Let me interject with this: I have already looked in the Mozilla Support system and have found a discussion of this problem, but the solutions proposed fall into two categories: (1) things I understand, and have tried (e.g. creating an exception for Thunderbird in my AV program), but that haven't worked; and (2) things I do NOT understand and am therefore nervous about pursuing (e.g. "make sure the files system allows you write privileges" -- I don't even know what that MEANS, let alone how to fix it). I have thought, based on a few things I've read, that creating a new profile might help, but this leads me into uncharted territory, and makes me nervous. So, a plea to whoever might respond here: I am NOT a sophisticated computer user, so whatever advice you give me, feel free to dumb it down as much as possible. (I will not be insulted if you address me as though I'm an idiot; in this realm, I am.) Thanks in advance for any and all help.

My Thunderbird client install on a particular PC had a crash yesterday afternoon, and it appears that I have lost my folder structure and sent folder for one of the 5 email accounts that is set up in this client. The rest of the accounts in this client setup are fine. The account that experienced the crash was set up as a POP3 account, so I cannot just reload from the server. Unfortunately I did not back this thunderbird profile up recently enough. Is there anyway to recover what was lost? Is it hiding somewhere on the PC? ANy options to try?

Suddenly Thunderbird takes a long time to download even a few (10-20) emails from Gmail and then it freezes on an email and as I click on different emails only the original one shows on the bottom half of the screen, even if I change to a different folder/email account. Also it will not close when I hit the X in the upper right corner.

If I click on one of the other apps, such as Calendar it goes to calendar but when I go back to email it still shows that same frozen email.

I tried clicking on the three bars (hamburger) to find the Thunderbird version and nothing happens.

I have restarted the computer but that has not helped.

This is an add on to the previous portion that I wrote yesterday. Today nothing shows in the portion where I usually view the message after I've clicked on it. Also the options in the tool bar such as File, Edit, View etc. do not respond to a click after the first time I have attempted to look at a message.

I am considering uninstalling and reinstalling. If I do that will it find all my emails and folders etc. again? There are a few emails that I am quite desperate to access that I have put in folders.

I'd really appreciate any help I can get on this as some important work is being delayed until I can access those emails.

Thanks for any assistance!

Good morning

Since this morning (05/03/2026) Thunderbird freezes within a minute or two of opening the program.

Everything in the program freezes up. I cannot even close it.

I am running Version 140.8.0esr on a Windows 10 PC.

Initially I was getting a pop up warning message that ask me to confirm if I wanted to send an email with attachments of over 20 MB. There were 3 or 4 such messages. I had not tried to send such emails.

I checked the Outbox in Local folders for old messages, but it was empty. I also checked the Unsent messages files in Local Folders in the Profile folder. I deleted the Unsent Messages.msf file to no effect. I renamed and replaced the Unsent messages file. Also no change.

I checked for crash logs but there are none.

I have run out of ideas as to what to try next. Does anyone have any advice?

I have a fairly old Thunderbird ESR Flatpak installed on my System76 Meerkat. Yesterday, it was working just fine. This morning, it refuses to launch, giving no error message from the desktop, and behaves as if something has been deleted.

Other than being slow to download my emails now for a few months, TB was performing well until a week or so ago. Now it also won't open the downloaded email when I click on it and the TB freezes up so I can't close it out. I have tried restarting computer multiple times and it works for one or two emails that I can open and then starts freezing up again. Makes using it almost impossible. I have security Windows 11 Defender only and have had it the entire time when it also worked well.

I am running Windows 11 Pro 25H2. After updating Thunderbird recently to the latest version, it is crashing immediately upon starting Thunderbird, not even bringing up the initial screen.

The message is

"Thunderbird has stopped working. A problem caused the program to stop working correctly. Please close the program."

In addition, it brings up the Mozilla Crash Reporter, which states

"We are sorry

Thunderbird had a problem and crashed. We will try to restore your tabs and windows when it restarts."

I do not want to lose all my old POP3 messages, etc.

Please help, Nina

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.

well installed Thunderbird on UBUNTU 24.04 LTS doesn't start beyond choice of new profile and selection of old data file from a former UBUNTU installation (UBUNTU 25.10 ) I retrofitted to current UBUNTU 24.04 LTS , thus more stable

For two days I'm having intermittent "hanging" when I'm typing a document or letter in Thunderbird. It has just dont that for the 2nd time in less than 10 minutes. Don't know what's happening but it's very frustrating. Am not having any other computer problems. Am running Windows 11 which is automatically updated by Windows. I think Thunderbird is the most current version too. Help please anyone! It does say "(Not Responding) at the very top of the page.

Greetings, I've been using Thundrbird for many years, and now suddenly it won't open, because of a "Bad Image" error. Is Mozilla Thunderbird still usable on Windows 10? This started happening either yesterday (maybe yesternight) or the day before yesterday.

"--------------------------- thunderbird.exe - Bad Image

C:\Program Files\Mozilla Thunderbird\lgpllibs.dll is either not designed to run on Windows or it contains an error. Try installing the program again using the original installation media or contact your system administrator or the software vendor for support. Error status 0xc000012f.

OK

Thunderbird

Couldn't load XPCOM.

OK

"

Should I try to reinstall the newest version 150.0.2? I have downloaded it, although I just checked the file version, and it's already updated.

Thank you, Shalom

I have accidentally opened up hundreds of mail I meant to delete. I cannot access my emails, Thunderbird keeps failing to respond. I have tried closing each tab but I cannot tell what is going on. Help please. I can't give the version as it doesn't respond to any instructions

After Windows installed an update in the middle of the night I can't open Thunderbird and I've tried uninstalling it and reinstalling with success.

It says: Thunderbird is already running, but is not responding. The old Thunderbird process must be closed to open a new window.

I've rebooted the PC, shut down the PC, ended the task and still nothing. It seem that Thunderbird didn't shut down correctly and the system still thinks that it's open and running. Anyone know how I can fix this issue?

Thanks,

Gregg

När jag ska starta E-postprogrammet går det inte. Jag får först meddelande om felstatus Oxc000012f. Sedan får jag kan inte ladda XPCOM. Vad betyder det? Måste jag ladda om programmet. Jag har använt programmet i många år och har mycket infor och kontakter där. HJÄLP

A few weeks ago, my Thunderbird went very, very slow. It has from time to time crashed. Now this happens whenever I start a new email. If I downloaded Firefox, would that help?

I have followed all the other recommendations with, no luck. I am on Windows 11 and use Eset virus software. Thunderbird is not listed as running it Task Manager, and there is no Profile.lock (think that was what it was called) in the profile directory, and I have deleted the existing profiles and recreated it. I have uninstalled and reinstall Thunderbird, and I have rebooted my computer. I am frustrated and concerned I will loose saved emails and my address book! Help.

I am running Fedora 42 KDE spin ("plasma"). The "Discover Software Center" app offers Thunderbird as both a regular and a flatpak install, and I somewhat arbitrarily chose flatpak.

I am dealing with several legacy email accounts that have 20 years of messages, so I need to control where the profile was created, so immediately after installing I ran with -P to create a profile and specified a path name of /lore/jeff/thunderbird. /lore is the mountpoint of /dev/sda2 and it is in my /etc/fstab. /lore/jeff previously existed because that's where I put my Dropbox folder.

Every time I shut down TB and restart it later it always fails because lock and .parentlock are never deleted. Until now, I just dealt with it by deleting the files in bash, but today I wanted to make sure that TB always starts offline and decided that user.js would be the absolute safest way to guarantee that, so I pulled up profiles.ini to get a list of all profile paths to make sure that I put a copy of user.js in each and every one whether it's in use or not. What I discovered is that the profile I created does NOT have a Path of /lore/jeff/thunderbird but instead /run/user/1000/doc/e1a4ab74/thunderbird and not only that but at the very bottom of the file are these three lines [InstallBD520B11F73A6B64] Default=/run/user/1000/doc/e1a4ab74/thunderbird Locked=1

The interesting thing is that when I put user.js into the /run/user... path and then looked at /lore/jeff/thunderbird to check on lock and .parentlock, I see that there is magically a copy of user.js there. I'm not exactly sure what is going on because when I do `ls -ldi` on the two files, their inode numbers are vastly different. I don't know enough about how flatpak operates internally, but my gut tells me it has something to do with it, and my question that I'm finally getting around to asking is if I edit the profiles.ini file to use /lore/jeff/thunderbird in an attempt to get TB to correctly clean up the lock files, is that going to cause a problem because of whatever flatpak is doing? And should I complain to flatpak about it?

Thanks for reading :-)