Thunderbird Community Forum

Dell windows 11 computer self destructed and crashed hard. Lost Thunderbird emails but have an Acronis cloud backup. Have purchased a new Dell EBT 2250 computer with windows 11 pro.

QUESTION 1: What are the proper procedures of installing Thunderbird and recovering my past "stuff" which was located at C:\users\My-Username\AppData\Roaming where Thunderbird kept my email data..If I install Thunderbird on the box, it would create that structure to create the Thunderbird data folder.

QUESTION 2: What are the proper procedures in recovering Thunderbird past data before I open it to my email server (Yahoo) where I have directly been maintaining my new emails via browser. I was going to install Thunderbird, then replace the Thunderbird folder under the user/username/AppData/Roaming, but when installing TB forces you to give an email account and P/W to log into your email. I do NOT want to have the email at Yahoo brought down before I can confirm I have restored all my past emails from my backup Thunderbird fold.

Question 3: Is there a way of installing TB in order to get the structure it uses, then overlay the TB structure under my user id?

I didn't want to restore my new Desktop with the OS recovery method because of the completely different hardware that OS would encounter once it tried to come up under a completely different hardware environment.

Thanks to anyone who can help me in what I should do, Floyd Smith

Yesterday I was having trouble sending emails from one of my email accounts. I had not fixed that when I shut down for the night. Today when I turned my computer on, both my email accounts and my address book was gone

06 May 2026 USA Just to inform users:

All mailboxes and all mail in profile are catastrophically and irretrievably deleted when I: 1. Change the location of the profile folder. 2. Make appropriate change in profiles.ini reflecting the location change. 3. Launch Thunderbird in Offline Mode (launching in OFFLINE mode is the fatal event). 4. Mailboxes will appear during this one launched session

    but

5. If Thunderbird is closed while still OFFLINE, then a re-launch of Thunderbird in any state will reveal

     that all mailboxes and all mail have been deleted.

All mailboxes, and of course, all mail in the profile are catastrophically and irretrievably deleted. I was lucky that I made a backup before changing profile location.

The deletion of mail and mailboxes occur at the close of Thunderbird's OFFLINE state. An examination of the profile folder indicates the destruction has occurred upon closing of Thunderbird in OFFLINE state.

It is not the re-launch of Thunderbird that causes the catastrophic deletion. The deletion occurred when Thunderbird was closed in its OFFLINE state.

To successfully change the profile location I must: 1. Make the change to profile location. 2. Make the appropriate change to profiles.ini 3. BE SURE to make the FIRST LAUNCH of Thunderbird in ONLINE mode--ONLINE only. 4. Once 1,2,3 are done, then Thunderbird does not corrupt the profile folder.

Conditions that MIGHT make my configuration uniquely affected: 1. I use Proton Mail Bridge in conjunction with Thunderbird. 2. My Profile folder is on a network share that is letter-mapped in Windows. 3. I have about 10 email addresses in Thunderbird that are Outlook IMAP, Gmail IMAP, and of course, Proton Mail.

I've been using Thunderbird a couple of years in this configuration with no problems. I just decided to rename my profile. So, this is my first discovery of the problem.

My wife and I both have Thunderbird accounts. The issue is that when we open Thunderbird, both accounts show on one screen. Is there any way to separate logins and only show each of our accounts on the screen?

Thanks, Sam Orner

When I opened Thunderbird two days ago it came up with the following message: To use your current email address, fill in your credentials. Thunderbird will automattically search for working and recommended server configurations. It asked for Full Name; Email: and Password. Fearing it was a scam I filled in my server settings manually. My server is Centurylink but my email address is embarqmail.com so when I filled in my info the send was smpt.centurylink.net port 587 (which was fine) The problem was with receive: I guess my old setup was pop.embarqmail.com port 110 and I put in pop.centurylink.net port 995 which is what Centurylink's website called for. Well this one worked and it downloaded 800 messages but no saved folders and the Thunderbird screen layout looks different from the one I am used to. A few minutes later the pop.embarqmail setup downloaded the same messages but still no saved messages. It looks like I have 2 profiles. Did the last one I entered override the old and wipe out files I had stored. Is there a fix for this mess I have created and can I retreive my old folders and messages? I tried doing a system restore and it didn't work due to corrupted files. Oh, I'm still using windows 7. Thanks

Thunderbird is suddenly opening without any of my emails or folders, and asking me to set up an email account - so I put in my email details (I'm with aol) - and it connects to the aol server and my folders re-appear (initially without emails in them, but when I click on the folders the emails start downloading afresh from aol). So it seems that all will be well when the emails are all downloaded again. HOWEVER, after closing Thunderbird and opening it again, all my emails are gone again, and Thunderbird is yet again asking me to set up an account. I can do this again, and the same thing will happen again. Everything is lost again when Thunderbird is closed, and when I start it again, I will be asked to set up an account, and all my emails are gone yet again. I have been using Thunderbird for years and years and years. Suddenly out of the blue this happens, and I'm stuck with using aol's web mail platform directly (not great!!!) Also, Thunderbird suddenly looks different - like it's been updated (which I assumed initially had happened) but the update history still only shows the final release for Windows 7, so this is a bit puzzling, and an odd coincidence that the layout and appearance of Thunderbird has changed at the very same time it stops working for me.

I cannot get thunderbird to run on my computer (it runs fine on my wife's computer). I keep getting the profile can't be loaded error. I have tried the fixes recommend here but none worked.

Have been using the 104.9.0esr 64-bit release on Windows 11 for some time now (mostly for email, involving a number of email accounts) and have been generally satisfied...

...but discovered when I started looking into switching over to the 145 default release that I have a capital-P Problem. The first thing recommended on making that change is - sensibly - to back up one's Thunderbird profile. Only as far as I can tell, I don't *have* any such file anywhere on my system. [To answer the obvious question - yes, I've got "View" set in File Explorer such that it should be showing me hidden files.]

I have drilled downward through all the USERS subdirectories on my C: drive. "Default" and "Public" have nothing at all (as one might expect). My personal subdirectory has a Mozilla directory under "Roaming", and both a Firefox and a Thunderbird directory therein, but the only things in the Thunderbird directory are an empty folder labeled "Crash Reports" and a tiny "desktop.ini" file.

There is a "Mozilla Firefox" directory under Program Files, but nothing in that hierarchy looks applicable. There is a "Mozilla Maintenance Service" directory under "Program Files (x86)", but nothing there appears relevant. There is a "Mozilla [alpahnumeric hash]" subdirectory under "Program Data", but nothing there appears relevant.

And in fact, I begin to think I have a bigger issue than I thought I did...because the more I poke at my C: drive, the less I'm seeing...to the extent that I'm not at all sure where the Thunderbird program itself (not to mention a quite large accumulation of associated email) is being kept.

Which would be nice to know if one were attempting to back up one's mail before changing program versions....

Hello- I am having a major problem recovering both emails in my inbox, and more specifically all of my local folders. I am using Windows 11, Pop-3 server. My Local Directory keeps reverting to att-1.net and changes I made to my prefs.js file to eliminate the att-1.net folder and revert to an att-net folder containing all the data are not sticking. I've tried using Claude to diagnose and correct, but that hasn't worked. I am not extremely proficient at this, which is probably part of my problem. Any advice would be welcome.

Help please I want to use "Personal Backup" program to save a backup of data needed to restore thenderbird Using tools>help>trouble shooting>application basics>profile>open folder gives 5 files all ending in .default 3 are 1 KB - can these be deleted? 2 have more folders each with many folders and files- are they both needed? which do I use for backing up with "Personal backup" program? the "Personal Backup" program finds 2 possble profiles defaultuser and default_user, which do I need? I am on the "release update channel"

Believe my T-bird account has somehow been corrupted. Takes forever to load on PC and always puts new emails in Trash folder. Often does not accept correct password. If I save / backup PROFILE, uninstall T-Bird and delete any Thunderbird folders on PC, if I restore per backup, will I be restoring the corrupted app. Don't want to loose email addresses, thousands of emails and email folder structure. Will a restore work? Thank you. Greg D

PS Version of T-Bird on laptop still puts all new email in Trash, but loads much more quickly, etc.

I tried to transfer Thunderbird file from old computer to new computer but get "Profile cannot be loaded. It may be missing or inaccessable." when I start Thunderbird. The old TB file works on old computer and I am pretty sure I copied it and pasted it into the new location in place of the current Thunderbird file.

Hello. I recently upgraded from my older MacBook Pro (now factory reset and sold) to a new MacBook Air. I use Thunderbird as my email client and I have many folders that live within my Local Folders. When I transferred all the data from the older Mac to the new Mac via iCloud, and set up my new mail account (IMAP), the folders did not download into the program. I've tried using Subscribe but none of my pre-existing folders show up. Any assistance would be much appreciated. Thanks.

I have my incoming IMAP emails stored on my local computer drive where the default Thunderbird installation puts it. This is fine.

My question is, can I move the local folders directory to another external drive or network attached storage? I am doing this as I have a small local SSD and combining all emails the size is massive.

I want to move my TB data store to a different drive but am unsure whether just to move the profile folder or all the other stuff like installs.ini as well. I have changed the datastore entry in settings, but do I need to modify the profiles.ini file as well, and if so what should it be changed to? At present it is in c:\users\mike\app data\roaming\thunderbird and I want it to go to D:\mail profiles. I'd be grateful for advice please. Thanks Mike Phillips

"Your Thunderbird profile cannot be loaded. It may be missing or inaccessible" keeps appearing mid-screen. version 147.0.1 re-installed several times (Win-10). Transfers of profile attempted from operating PC (Win-10) Cannot locate profile even in a "fresh Install" although the shortcut appears on screen and other associated files seem to be installed. Helps have been downloaded and tried. Same issue. I've received help suggestions from Lin and sfhowes both on 2-6-26.. Thanks for your help.

I recently upgraded Thunderbird from v140.7-ESR to v147-Release and would be grateful if someone could answer some questions.

After upgrading I noticed there are 3 profile folders even though I am the only user of my Win11 laptop.

Profile Folders 92yfgi88.default-esr - 3.654 GB - 2026/01/23 12:50:27 >> My profile jf63jfuk.default-default - 1.533 GB - 2024/06/05 21:27:32 y9efj7q9.default - 47 Byte - 2026/01/23 12:30:15

The folder y9efj7q9.default only contains 2 files - parent.lock (0kb) and times.json (1kb).

1. Can I safely delete profiles I don't use?

2. Why is -ESR still shown at end of my profile folder name? - I thought it would be renamed when I changed to the release channel version.

3. Can I manually rename my profile folder? - I know I can rename a profile using Profile Manager but this doesn't rename the folder.

4. If not possible to rename my "92yfgi88.default-esr" folder, I assume I can just copy it's contents to another new profile folder and tell TBird to start using that?

5. Can I use Windows File Explorer to delete/rename profiles, or must this be done from within Thunderbird?

Also, any idea why Thunderbird Notifications still show as coming from Mozilla Thunderbird ESR, even though I now use the Release version? I've checked Windows 11 System > Notifications and it is still shown there as Mozilla Thunderbird ESR.. Why? and how to fix?

Thanks in advance..