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After a reboot and Windows 11 update today, Thunderbird (I believe it was v155) will not open. It asks for the password, then sits at [Not Responding].

I have copied my profiles (there are two, one dated 2023 with only a 1K .json file in it, and one created tonight while I was troubleshooting that's several GB and when copying, appears to contain all my mail folders although I can't access them directly from within the profile) to a separate location (my desktop).

I've tried the following (after checking previous questions here in Mozilla support):

(1) booting Windows into safe mode

(2) opening Thunderbird in Troubleshooting mode (Shift while opening), both in Windows safe mode and normal boot

(3) uninstalled Thunderbird from Control Panel, downloaded and installed a new copy of Thunderbird

All give the same result: "not responding", can't click anything. Can only wait or close.

I was able to disable an extension that I installed yesterday that had been working fine.

I'm also wondering if the problem is mail folders that are too large. I have some candidates for deletion but since I can't see any .msf files for them, I can't delete (because I can't open Thunderbird.

I'm leery of instructions to outright delete any Thunderbird folders/files because (1) I can't see my mail folders directly and (2) I'm self-employed and all my client and business emails are in there. Losing them woud be a disaster.

I'm tempted to try the Windows option of restoring my entire computer to an earlier point, say, this morning. But that seems like possible overkill if it's an issue with just Thunderbird.

I'm freaking out, please help!

I cannot open the email program with Thunderbird, I have trie to open it by pressing Shift and Thunderbird Icaon, thus the Repair menu opens, I have tried every combination in that , like starting in the secured modus, but it did not help, I have tried to delete the "parent-lock" data in %appadat%\Thunderbird\Profiles\ - it said that I cannot delete it,because it is opened in Thunderbird. Would you kindly help me? Thank you very much

Mozilla Thunderbird stopped responding, tried to shut down, restart, uninstall and install - nothing helps Still opens the window, but no messages white backgoround and (Not Responding)

Since the 152.0 update I've experienced near nonstop browser crashing, it crashed twice as I was trying to type up and submit this message,

Is this a known issue or solely on my end? running 64 bit, windows 10

My browser started crashing after the latest update, and it still crashes even in Safe Mode. It doesn’t close immediately upon opening; instead, it shuts down suddenly after about one minute or longer. This issue never occurred before and only started appearing after the recent update. My system is Windows 11, with the following detailed information: Edition: Windows 11 Pro Version: 23H2 Install date: September 17, 2023 OS build: 22631.5624 Experience: Windows Feature Experience Pack 1000.22700.1106.0

610c857a-a2cb-4418-acab-c5427191921a 6/18/2026, 1:48 PM a8a404a8-d04f-4ab9-a983-bee673c80a81 6/18/2026, 1:45 PM 9369f2bf-e222-40c9-8891-459f2fc4c135 6/18/2026, 1:15 PM 45e527f4-d682-44cc-87bb-7e53c62166cd 6/18/2026, 1:01 PM 43ed298b-1639-45e3-b57d-af22242193f5 6/18/2026, 12:57 PM e283cc13-e637-484f-b540-7b38bf9451fd 6/18/2026, 12:46 PM 77f667a2-e11d-4ca5-99fb-b45d03a58d39 6/18/2026, 12:43 PM

I usually use firefox to download things, and watch videos, however, sometimes, when I change tabs, try to minimise firefox, close a pop up, even if I just pause a video, it randomly decides to instead completely freeze and require the app to be completely restarted, and it occasionally decides to roll back my search history.

In fact, Firefox crashed as I was writing this, i'm lucky my progress was saved, these issues have made firefox completely unusable about 70%-80% of the time, and i'm running out of browsers to switch to, opera is run on lies, chrome is just bad, and now firefox is dying.

Just for reference, no other application or web browser that has ever been on my current device has ever acted like this, I'm currently using a decent PC running Windows 10

While playing Free Games.org and Free Mahjong also on AOL Mail Firefox crashes after a few moments. I performed security scans and restarted, still crashing.

Firefox keeps suddenly crashing, I have reset Firefox, deleted it and reinstalled it, I have used DISM and SFC to repair any issues and I have set up a new profile within Firefox with no extensions, but still I have the same issue, either tabs suddenly crash or the whole Firefox does.

Following my traumatic brain injury I do have a reading disability search that perusing your articles could take me up to a week.

As you see I am running Windows 10 on a laptop which Microsoft said I was good for another year using this OS. Your latest download executed and after 2 reboots continuously crashes after trying to view any of the five windows a browser I had open with multiple tabs in each.

Hello, Whenever I open Firefox, it crashes repeatedly. This has been going on for at least a couple of weeks, whether it's right when I open it or hours later when I'm in the middle of something. I've disabled extensions, ran it in troubleshoot, and done the steps advised to no avail. Any help would be greatly appreciated as this has rendered Firefox unusable. Attached is a screenshot of the digits of the crash reports, as well as the link for the one from today.

I don't want to spend any more on my PC. It was the largest amount of money I had ever seen when I first bought it. Even if I have way more resources now, I don't believe that a few faulty locations in my memory should be causing so many problems for myself and for developers who have no clue why their users keep crashing.

It is either my RAM or VRAM. Disabling XMP on my RAM dampened these issues but couldn't fully solve them.

It's exactly as I said. Normal programs just crash. Kernel-level programs or anti-cheats can entirely blue screen my PC. It all has to do with where these programs are writing to in my hardware. It's only a few locations that I have faulty. Most programs work fine. Most games work fine. Most crashes are very transient.

Firefox is a transient and common crasher for me. It's so painful to be scrolling a page and have the page crash, just for the previous page to load instead of the newer one that I was on, and on top of that I could also be losing work or effort.

I know this isn't exactly a dev support page, but this problem is so recurring that I don't know what to think anymore. There has to be a way to check which memory locations are fried without causing a bluescreen or crashing the program. Maybe it's a Windows issue and devs could easily fix it, if it weren't for Windows bottlenecks like labelling the faulty locations as "protected". I've seen at least 1 crash where the output said something like "Error: tried writing to protected location" blah blah blah then it spit out some hexcode or exact location and blahblahblah. And that was the entire error message.