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1. 1. Steps to reproduce

Open several tabs, in settings, check «ouvrir les fenêtres et onglets précédents», quit firefox.

1. 1. 1. Expected behavior

On startup, Firefox should reopen with the same tabs before shutdown.

1. 1. 1. Actual behavior

Firefox opens with one empty tab. Forcing me to got to «history -> recently closed windows -> restore» everytime I quit Firefox or shutdown the mac.

1. 1. 1. Device & build information

• Device: MacOs Tahoe 26
• Build version: firefox 148.0.2
• First seen version: MacOs Sequoia

1. 1. 1. Notes

Fresh migration from Win 11 to Mac. tabs, passwords, bookmarks, plugins migrated from win to mac. Attachments:

Importing CSV address books does not work properly. The resulting folder cannot be accessed by emails to be sent.

The imported Address Lists cannot be used in an email as a list. The error message is that the address is not a valid email address. However, if a new Address List is created with the contents of the imported file manually copied, then it can be used as an email address.

I also found that clicking on an individual address in the imported csv, will open the individual email address.

So the addresses are valid but the list is corrupted.

Hello,

I downloaded all my emails from my .com mailbox into Mozilla Thunderbird. I could see all of them for about three days, and I was very happy to have them stored locally, as I am planning to move my mailbox elsewhere.

However, today all folders appear empty in Thunderbird and I can no longer see the emails, even though I can see that the files are still stored on my computer.

I have been trying for hours to solve this problem with the help of AI, but without success.

Could you please help me restore or display the emails that were downloaded locally?

Thank you very much for your help.

Best regards, Michaela

Four accounts: Rogers Yahoo, Office365, GMX, and a second Yahoo account

When Thunderbird recently asked to access to my provider's server, I gave my Rogers Yahoo account and password; everything looked fine. But when I tried to use my second Yahoo email account, all the folders contained the same data as the Rogers Yahoo account, even though the email addresses were different; my original emails were gone from the Inbox and other folders.

So I began to follow the instructions in Mozilla's page "OAuth2 Authentication for Yahoo, AOL and ATT". 1) with Config Editor, changed "mailnews.oauth.usePrivateBrowser" to TRUE 2) checked for "Accept cookies from sites" in Privacy & Security settings 3) checked authentication settings: All Outgoing servers were set to "OAuth2", as well as Yahoo and Office365 incoming servers. The GMX incoming server was set at "Normal Password" with no option for "OAuth2". 4) I am in Canada and do not use VPN. 5) Finally, I deleted the second Yahoo account (tc2002ca) and all its data from Thunderbird. I logged into Yahoo! Mail online to make sure I had the correct password. I then added tc2002ca as a new account using manual configuration. I entered all the settings to match the Rogers Yahoo account, except (of course) the password which was associated with the tc2002ca account. The result: same as before - all the folders of this account were identical to the Rogers Yahoo account.

To summarize, all the settings in the two Yahoo accounts were the same (imap.mail.yahoo.com and smtp.mail.yahoo.com) except the passwords. When I "tested connection to server" in each case it came back "Successful". Please help me get back to having two Yahoo accounts in Thunderbird, as I have had for years. By the way, I have had no problem using SeaMonkey in a similar way. Thanks!

As soon as I click on the Thunderbird Icon to start Thunderbird I get a Yahoo Page covering over my Thunderbird page with no practical way to remove the Yahoo page permanently? This is like a scam page or something from a devious hacker?

Using Acronis True Image for Western Digital (ver 2025 build 41936) to backup my files on a daily basis. Recently the backup program has been stopping and reporting that it cannot access some Thunderbird files, even when Thunderbird was not running (1st image) I tried 'Compacting all Folders' in Thunderbird but the result was the same (2nd image). Lastly, I tried clearing the cache - the result is the same. In all cases Thunderbird was not running during the backup.

i realize that this is not a Thunderbird issue, but I've been unable to get help elsewhere. I wondered if anyone might have a solution since Acronis apparently sees the file as being accessed - is there a way to remove that?

I am running Thunderbird 140.8.1esr on macOS Tahoe 26.3

I created an IMAP account in Thunderbird to replace a POP account

I want to copy the Thunderbird message filters from the POP account to the IMAP account

I read articles on Mozilla Support and these said to copy the msgFilterRules.dat file but I cannot find this file

How can I copy the message filters?

I made a folder and saved emails in that folder. A few days later they were all gone, empty folder. I followed suggestions on here, did the repair, erased password and replaced it, did the subscribe, and now even the folder is gone. I spent hours trying to research this and repair it and now I have nothing.

I just accidentally deleted a day of history, now it has to relearn a bunch of stuff.

Please add support for undo, so that if you do it by accident, you can reverse it.

What seems like ages ago Firefox stopped displaying bookmarks I addition it would not add new bookmarks nor restore the existing ones. I've gone through all of the corrective procedures listed on and off but nothing works. As a final attempt I deleted the program and reinstalled it. No change. It seems to me that perhaps a missing file from another program or system is missing. Maybe!

I have been using an alternate system for some time. When installed it had no problem finding all of the Firefox bookmarks and placed them on the menu bar as "Firefox Bookmarks". I have no issues with using them but all new ones are stored in the current browser. Thus the new ones do not go into the folders previously set up. I've avoided moving them manually to the new system due to the volume but I am ready to bite the bullet.

I prefer Firefox but it's just not working.

Can anyone save Firefox for me.

Following https://support.mozilla.org/en-US/kb/troubleshoot-firefox-crashes-closing-or-quitting

Crash Reports (Newest to Oldest, starting with troubleshoot mode: https://crash-stats.mozilla.org/report/index/bp-c5831b14-736e-4a37-a0f5-9eb170260310 https://crash-stats.mozilla.org/report/index/bp-ed2fcada-4566-4a83-9adb-5554d0260304 https://crash-stats.mozilla.org/report/index/bp-74a45b0c-663a-4c0d-981a-460cd0260304 https://crash-stats.mozilla.org/report/index/bp-98feeed5-7fef-4c7b-aaa9-562930260303

Occurs since end February, so probably since 148.0-1 Always in the same place in libgio-2.0.so.0

I will try to roll back to 147.0.4-1

As of yesterday my Firefox browser no longer displays some screens within Amazon Prime correctly. It displays what should be images as text, which is difficult to read, unlike Microsoft Edge, which displays the Amazon webpage correctly. I am running Windows 10 with a support extension through October 2026, so could it be an update from Microsoft Windows or Mozilla Firefox that has caused the problem. Thanks for your help.

Michael Archer [edited email from community support forum]