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Ich habe eine Systemwarnung halten und habe versehentlich angeklickt. Defender hat einen Trojaner entdeckt. Dieser wurde entfernt. Jetzt wollte ich Firefox restaurieren. Wie ist das möglich. Was ist zu tun ?

I already have Firefox on my laptop and via Mozilla I was asked again to install Firefox. Furthermore I always got the question that I should use it as standard browser. I have no idea what else should I do in that case. If I would install again Firefox, I will lose all the paid apps which run already on the current version. So I am really very confused about the characteristics of this Firefox installation and the strange requests by Mozilla to install Firefox.

I would be delighted if you could me support with checks to find out about the nature of the current Firefox installation or a simple de- and reinstallation instruction of Firefox (and keeping the paid apps like Ad Blocker...).

Thank you in advance for your feedback

Rosemarie

I have downloaded Thunderbird from official Mozilla homepage. It seems to be installed correct. I got the icon and a question : should we start Thunderbird now. I answer yes. Then I get the message : Thunderbird is not found ? but I have just loaded it ? I am running windows 11 and I have got newest upgrade.

Hope you can help me out. Thx in advance. Regards Thorvald Antvorskov

PS I also have a PC running Linux Mint. Loading Thunderbird here was no problem.

New computer, trying to install Thunderbird. "Download" created a file called Unconfirmed 750544.crdownload which isn't executable and doesn't seem to do anything. How do I proceed to do an installation?

I'm trying to switch from Thunderbird ESR (140.8.0esr) to release (148.0). Following the Mozilla support recommendation I'm running the 148.0 setup and trying to install it to the same directory. While doing so I'm asked to restart the computer. After doing so I'm required to restart setup but continuously asked to reboot the computer. is there a zip version of the installation? if not How to overcome the restart issue?

I am trying to re-install Thunderbird on my wife's old Gateway desktop. I downloaded version 115.18.0 and tried to install it, but get a message saying it can't be installed because my OS is 32 bit. I thought the SuperNova would work for both 64 and 32 bit OS platforms. (It does work on my Toshiba laptop, which is a 64 bit Win 7 machine.) If this version of Thunderbird will not work, what about the last version that will. It was installed years ago. Thanks, Peter

Okay, I currently have two issues going on, both repercussions from transferring Thunderbird to my new computer. I'll limit this post to one issue!

My transfer to the new computer was not taking; followed instructions but no profiles were loading. I thought that perhaps this was due to my initial problematic installation of T-bird decades ago, where I eventually wound up with a choose-user-profile panel that worked fine with its default setting...so I lived with that easily (see image). Thinking that this was causing the inability to load profiles on the new machine, I tested whether I could delete the never-used profiles in that panel. After just one deletion, that resulted in the "Couldn't load XPCOM" error described here: https://support.mozilla.org/en-US/questions/1360766 Following the instructions on that page to do a repair installation (to the letter), starting T-bird now results in the attached "profile missing or inaccessible" message.

Please advise: Am I doomed?

Thanks for any honest advice. (yes, my Thunderbird installation is big: seven or eight addresses, many local folders, a large history and archives.)

We tried installing Thunderbird on two PCs, both running Windows 11, but with unsatisfactory results. In July 2025, we bought a 15-inch HP PC running Windows 11. Thunderbird was installed, and the sending and receiving functions worked correctly with one domain name and three email addresses linked to that domain name. In January 2026, we bought a Lenovo T14 PC running Windows 11. We tried installing Thunderbird with the same domain name and three different email addresses linked to that domain name. Result: On the T14, it was impossible to install the third email address; only two addresses could receive and send messages correctly. Furthermore, the 15-inch HP PC now receives messages but can no longer send them; the connection is rejected by the server. Analysis: Apparently, there is an inability to coordinate the two PCs for Thunderbird. Question: Windows 11 had numerous updates between July 2025 and January 2026. Do both PCs need to have Thunderbird installed the same version of Windows 11 ?