Firefox Community Forum

have no idea what this topic falls under but getting the update browser error code 99,999 again after restarting the damn computer when it just froze while I went out for 15mins I am updated so have no clue what to do

wish sending a question or replying to the email was easy but even that is b/s also this deny person claims bug fixed but obviously not

HERE'S HOW I SOLVED THIS "SECURE CONNECTION FAILED" ISSUE:

Kept getting this error when attempting to update Firefox; didn't matter which browser I used; went through the forum postings and tried every this-and-that-and-this-and-that posted there; didn't work; finally --

i opened a $10.00 30-day hotspot account with Xfinity, and the download worked perfectly.

PROBLEM SOLVED.

I have taken the position of never installing updates of firefox in windows 10 because of the following: after EVERY update, within 20 minutes of activity my mouse freezes. Keyboard is inactive. I have no option but to reboot. Windows displays "repair mode" 2 HOURS LATER ! the pc finally boots. This happens after EVERY upgrade. Since I have stopped upgrading, the pc behaves.

For past few weeks, Whenever I try to update FFX on windows 11, it fails. It takes me to another screen and tells me to download Firefox. When I try to download it , it aborts with this message.

"download.mozilla.org has a security policy called HTTP Strict Transport Security (HSTS), which means that Firefox can only connect to it securely. You can’t add an exception to visit this site."

To download Firefox with new version I have to use another browser but no choice. Then with new version of Firefox, I have faced the same issue of update and used same approach to update firefox to a newer version.

This error appears for some google sites as well but the same occurring for firefox download site itself is not understood.

Ajay

The Vanguard website warns me that my Firefox browser "is no longer supported" and must be updated. when I try to update, the message is "Firefox is being updated by another instance." what does "another instance" mean? how can I update it? fyi I run Windows 11 on my desktop.

Simply put, I continue to get a message window telling me to update Firefox. I continue to get a response saying I need Windows 10 or later installed. I am running Windows 11 Home on my PC. Multiple attempts to get a reply on this from Mozilla Support. No replies.

After the 8/5/25 Firefox update the internet is inaccessible on my laptop through the standard Firefox browser. The internet is accessible with MS Edge. Toolbar is set to always show bookmarks but none appear. Also, the browser's application's menu does not open to access options such as restore previous session, recently closed tabs, etc. I've restarted my device several times without it resolving the issues with the standard browser.

The Firefox developer version opened in command prompt safe mode (firefox -safe-mode), which is how this inquiry is being sent, but no bookmarks on tool bar or current page history from the standard (non-developer) Firefox.

I'd like to return to accessing the internet using the standard Firefox version with its bookmarks, history, etc. I am using Windows 10. Thank you.

Firefox was updated on my computer on 7/23/25. I can no longer access some of my applications. I tried Outlook and everything worked fine. Help me out here, everything was working just fine before the update, and I want to return to a working version. Thanx.

bold text I am booting up an older Windows 7 tower computer and wish to know how to update both Firefox and Thunderbird? The update popup seems to be stuck in download phase.

After the last update a couple days ago Firefox does not come up correctly. Search doesn't work. Duck Duck Go seems to be the default search engine and Google is missing from the selection list when the left mouse button is pushed. I really don't know how to describe the problem. It does come up in troubleshoot mode more-or-less correctly. Something odd happened during the update. A screen came up with some sort of message about having run into some sort of odd problem and that it would have to stop and restart the process, which it did. Hasn't worked properly since.