Firefox 社群討論區

Hello Firefox Support,

I am experiencing a consistent and disruptive performance issue that occurs immediately after certain complex web pages (particularly those with heavy scripting or dynamic content) have fully loaded.

The symptom is a temporary but complete freeze of the Firefox window, often lasting between 5 to 10 seconds, during which time the browser is completely unresponsive. This freeze is accompanied by a significant spike in CPU usage (often reaching 90-100%, according to Task Manager/Activity Monitor).

Details:

Trigger: The freeze reliably occurs right after the page status changes from "Loading" to "Done." I suspect it is related to post-load scripting execution or rendering finalization.

Impact: Any ongoing user interaction is halted until the spike subsides.

Tested Scenarios: I have replicated this on multiple sites, including heavy news aggregators, social media feeds, and complex web applications.

Troubleshooting: This issue persists even after:

Clearing cache and cookies.

Running Firefox in Safe Mode (disabling all extensions).

Creating a new, clean Firefox profile.

This severely degrades the browsing experience, especially when quickly navigating between tabs or starting a session.

Could you please investigate potential issues within the core rendering engine or script execution scheduler that might be causing these severe post-load processing bottlenecks?

Thank you.

I have Firefox (always updated to the latest version) and I have noticed a memory leak that EATS up RAM. I have 1 tab open, playing a set spotify playlist. within 24 hours of rebooting the machine, Firefox has swallowed 7gb of my Memory as shown in Activity Monitor/Memory Pressure. I've been having this issue for some time, updates to MACos make no difference either. NO other program does this. I've tested the same playlist in other browsers, Chrome, Safari, uses 1gb, brave/opera uses less than 500mb and they've been open for over a week. This memory leak is a bug in Firefox. I've seen it before (other software, mainly on Windows) but never like this on a Mac......How do I escalate this?

Hi, I’ve noticed that Firefox often uses a lot of memory when I have multiple tabs open, even more than Chrome or Edge on the same number of tabs. Sometimes it slows down my system or makes switching between tabs laggy.

Is this normal behavior, or is there a way to reduce Firefox’s RAM usage without losing performance? Are there specific settings, add-ons, or troubleshooting steps I should try?

Thanks in advance!

Since a while, I think it is since I created an extra testprofile with "firefox-esr -P", but I've set my main profile as default again

When opening a link in another program than firefox I get always: a popup "Close Firefox" "Firefox is already running, but is not responding. To use Firefox, you must first close the existing Firefox process, restart your device, or use a different profile."

I do have both firefox and firefox esr, I usually use regular firefox the second came with the debian 13 repository.

I keep the esr to test display issues for reproducibility on my personal desktop, because I manage debian 13 kiosk-style desktops with firefox-esr.

(I noticed also that the regular firefox profiles can not be opened in firefox esr, so I use an extra profile for esr)

Hi,

I'm using Powertoys Keyboard Manager to start Firefox from keyboard Shortcuts. It work almos perfectly except for focusing the newly started window.

The windows opens well, but i' have to click in it to take the focus of it, otherwise i can't type in address bar for example.

I tried to add -foreground in the shortcut parameters, but still not working.

Any idea ?

Thank you very much.

When i start fire fox it immediately opens 10 additional versions in the background which I can see in task manager and they take up a lot off memory. If i end task them they immediately come back. This only started recently. I noticed it because now when i open say a youtube video it shows it as number 4. This never happened before unless I had the same video open more than once.

If I can not stop this I will have to uninstall.

(My laptop is very slow. I have cleaned the cashe, performed disc cleanup, cleaned the memory, and everything i can think of. I opened task manager and see that multiple instances of Firefox open. (photo #1) I have uninstalled and reinstalled to no avail. I have also tried changing the preferences to 1 instance, but it wont allow me to. (photo #2) Please help.

I am using Firefox on my MacOS Tahoe. There is a persistent annoying issue where whenever I close (physically fold) my laptop screen and reopen it, Firefox will be frozen. It will be frozen in the sense that I am unable to interact with any tabs or anything until I manually quit Firefox and reopen it (which automatically reopens all my tabs), making it usable again. This doesn't happen every time I close and reopen my Mac, but it definitely happens the majority of the time and makes the browser hard to use.

I've attached a screenshot of what a new window looks like when Firefox is frozen. It looks just like a Firefox window when unfocused.

Notes:

• It doesn't entirely freeze Firefox. In fact, I can "switch" to a different tab by clicking on the tab and then shutting and reopening my laptop again. The new tab will show on reopening but Firefox will still be frozen. This process can be repeated.
• I can pretty consistently replicate the bug by shutting my laptop, waiting 10 seconds, and reopening it. This will almost always result in the freeze.
• The bug still happens if I'm not focused on the Firefox window but on a different app.
• The bug doesn't seem to happen if I just lock my screen but don't shut it closed.

Things I've tried that haven't fixed it:

• Updating my OS.
• Restarting my laptop.
• Disabling hardware acceleration.
• Disabling themes and extensions.
• Deleting and reinstalling Firefox, including deleting the user data in the "Library/Application Support" folder.

Let me know if there's any more information I can provide or fixes I can try. Also let me know if I should go ahead and file a Firefox bug report for this. Thank you.

I run a drafting site where we share shop drawings for contractors and architects: https://usadraftsman.com

Whenever I open these drawing preview pages in Firefox, the browser gets slow or sometimes becomes unresponsive. The same pages load completely fine in Chrome, so I’m trying to understand what might be causing this only in Firefox.

Most of the previews are large drawings or viewer embeds, so maybe Firefox is struggling with rendering them. I tried clearing cache and turning off extensions, but the issue still comes back.

If anyone has dealt with similar heavy graphics or rendering issues in Firefox, what should I check or adjust? Any suggestions would be appreciated.

I usually have multiple tabs open and my MacBook slows down and gets hot. Firefox is using A LOT of memory. Is there a way to have inactive tabs go dormant, helping reduce overall memory usage and improve browser performance? An advisor mentioned this is an option in Chrome. Is there a fix?

Thanks

Firefox prevents going into hibernate mode. It only appears to blank screen until mouse is moved or lid moved. This happened on 3 year old dell and now on new lenovo. I've gotten around it by going into task manager and killing firefox before hibernating. This doesn't happen on a newly opened window. I've noticed that as you use it, in the task manager, (not sure of correct term) the amounts of firefox tasks/threads? increases but does not decrease when tabs are closed. Eventually hibernate stops until I kill the firefox program. I thought this might go away with new lenovo with twice the ram, but happens at same rate. If I forget to kill firefox, I end up with a dead battery. This doesn't happen with edge or other browsers I've tried.

By addressing the problem that I have typed above. Why for over a year have I been getting 'Firefox not responding' message? I then have to start again every time. Thanks

Dear Firefox Support,

Since yesterday, I’ve been experiencing an issue where the entire browser randomly freezes for a few seconds. When this happens, everything stops — I can’t open or close tabs or windows, and I can’t type in the address bar. If I’m typing something when it freezes, the input seems to be stored in the background and then appears all at once after about 5 seconds, when the browser becomes responsive again. All add-ons are disabled, the computer has been restarted, and the latest version of Firefox is installed. This issue started just yesterday — before that, everything was working perfectly. No new programs were installed, and all other applications on my system are functioning normally. When I switch to Chrome, there are no issues at all. Thank you for your help.

Best regards, Peter

The lack of a title bar makes it impossible, for example, to close the application by pressing the "X" icon in the upper right corner. The title bar does not appear when the application starts, but does appear when the application window is minimized and then maximized.

I am receiving a not responding message when I try to use Firefox on my Dell Inspiron 3880 with Windows 11

I have tried uninstalling and reinstalling but get the same message.

App is unusable. Freezes up frequently. Tried downloading again. Same problem. I am using Chrome temporarily and it is working just fine. Also ran Safari, no problem. Used it to download ESR 115. Worked fine. Definitely a Firefox problem.

Selecting "Help About Firefox" causes the window to appear but this window then freezes with no information. It is possible to close the window and continue with Firefox. This happen nearly always but occasionally works correctly. Current Firefox version is 146.0 but the problem is not limited this version. System is Kubuntu 24.04, KDE Plasma Version 5.27.12 and QT Version 5.15.13 I have tried several things. Deleting the .Moziila folder will permit the window to work once but after a restart stops working. Any new things to try would be appreciated.

Firefox has been my entire family's browser of choice for as long as I can remember. Which one am I supposed to use now that Firefox won't quit shoving bloatware and diminished performance at me? I'm also seeing articles stating that they plan on making it even worse with more AI. I'm supposed to let them steal my data and turn my browser into sludge with absolutely no benefit to myself? And they're asking me to donate to them on top of it???

Does anyone know of a viable Firefox alternative that isn't a chrome dupe?