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Hi,

When switching from FF 128esr to 140esr our customers noticed a massive impact in performance for certain webapplications. All Applications effected heavily use pdf-files, users are working mostly exclusive in firefox. Performance is ok when the day starts but gets bad fast. Sooner or later working is no longer possible and firefox needs to be restarted.

The users work on Citrix Desktops, but difference in performance is also seen in Firefox localy (not as bad but its there). Cross-tests with another browser are not possible, because the application works only in FF.

We tried removing almost all policies effective to rule out a specific hardening setting We tried every setting we could find linked to cache (as it seemed related to that) but without success. We collected logs with the Firefox-internal Tools but could not identify a specific Problem.

Any Help is apreciated, thx in advance

What minimum memory spec is recommended for current Firefox usage? Have new computer with 16GB memory, 512 storage, intel core Ultra 5-225 processor & windows 11. Have not set it up yet.

First time using Thunderbird 143.0 (64-bit) on MacOS Sequoia 15.6.1. System is a MacBook pro 2.4 GHz 8-Core Intel Core i9 with 64 GB 2667 MHz DDR4.

Installed Thunderbird. Added a fastmail.fm and icloud.com account. Fastmail account is 14GB account. icloud is 50MB.

System is continually pausing during use and the mouse turns into the rainbow spinner. Application recovers after a second or two but it's annoying that it happens.

Thunderbird ActivityManager shows that indexing is not in progress. MacOS ActivityManager shows that CPU for Thunderbird going up to 100% during these periods.

Aside from the pauses, Thunderbird is stable and does not crash.

On a new tab in Firefox Focus for iOS 26, the floating keypad first appears, and once Dragged to bottom to make the full keypad, it glitches, erases what I wrote, and brings up floating keypad again. I know this is a beta and has bugs, this is just FYSA for iOS 26

I am running Firefox on Windows 10 64-bit, and I have lots of windows and tabs open. Occasionally I will get a message from Windows that I am running low on disk space. Recently I got the message, and I saw on my C-drive" "336,044,032 bytes free". After I did an Exit in Firefox, I saw "10,082,402,304 bytes free". The space that was freed was in the pagefile.sys file. Is this normal?

My computer, being 7 years old (and without the space to upgrade to WIN11), has always been a bit slow with low RAM and storage. The swap from Chrome to Firefox essentially gave it a second life, as Firefox didn't need a lot of space to run. Recently, though, it locks up with almost every search, refusing to let me x out a tab and try to save myself for 3 minutes or more, and the bluescreens have come back, too. If chrome hasn't also gotten worse, I'm considering switching back. Does anyone know what happened? I haven't installed anything new.

It's really frustrating and disappointing, because I thought I had a solution when I swapped to Firefox.

local folders after a certain amount of folders have disappeared. I have made a new folder today, it displayed, closed thunderbird, re-opened thinderbird, and folder disappeared, the .msl file and file are still in the profile/mail/localfolders directory, just not being display under local folders in program, deleted all .msl files, and restarted thunderbird, and it did not recreate the .msl file(s) as well

Hello! I have a question regarding Thunderbird version 144.0.1.

The server is configured locally and isolated from the Internet. There is an issue: when the network cable is unplugged (no network connection), saving received emails with attachments (for example, total file size of 14 MB) to the hard drive happens quickly — about 5 seconds. However, as soon as the PC is connected to the local network, the saving process for such attachments slows down significantly — up to 60 seconds.

I would appreciate your help with analyzing this issue and possible solutions. What could be the cause of this behavior?

Thank you!

Firefox runs in background even after menu quit option with clear all browser history (proper exit). Firefox heats my phone while using. I am using Android 13 phone.

Tbird (v16. 1) for android installed on my Pixel 9a connected to my gmail account. Gmail client runs perfectly connected to same account while Tbird starts with a blank screen i.e no messages. App appears to be frozen but later displays messages. General operation seems sluggish - enough to turn me back to the Gmail client (which I don't like) but at least I can navigate my email without waiting. Any suggestions please?

When I use Firefox to go to a url I have about 5 second max then it crashes. I’m running Firefox 144 on iOS 26.0.1. My wife is running Firefox 143.2 on iOS 26.0.1 and does not have this issue. Thanks. Mike

Third Contact. A few questions in hoping to resolve this on-going issue of Firefox 144.0 crashing on my iPhone.: What is GitHub … never heard of it? Why should I trust it. How is my privacy secured? Why do I have to go to GitHub for a Firefox issue? What is Xcode? How do I get it? How do I connect to it? After many years with Firefox why is this happening? Can I back grade to the previous Firefox? As a long time Firefox user and Mozilla donor a worse case option is for us to scrub FireFox from all of our systems pending Firefox issuing a corrective up grade.

I have been using Thunderbird for many years, and it's been a while since I cleaned out my Inbox & Folders. I get about 1200 emails a week, so the clutter is extreme. Yet it is still stable, and now I am waiting to see at what level it falls over. Currently I have 84,544 emails in my Inbox, 131,597 in the Junk Folder,33,718 in Archives, 13,388 in another Inbox, and a whole heap which get deleted when I compact the system.

I reckon compacting it has got rid of another 200,000 or so this year.

I am very impressed, well done guys.

[edited email from public support forum]

Hello everyone,

I have checked a lot of other questions already but I can't seem to find a solution to my problem.

I have Firefox installed on an old Laptop with macos Catalina. Reinstalled it many times with and without extensions, without any data but it doesn't matter what I do, even on a blank slate of a new reinstall of Firefox it just takes way too long to load or doesn't load at all and then even hangs up so that I always have to force quit it and slows down the entire laptop. It also sometimes loads tabs only if I reopen them or have to go to an already open tap that has been working to be able to open it.

I have been feeling super frustrated for days because I can not figure it out.

Thank you all for taking the time!