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Performance Issue Report: Firefox Unresponsive with High Memory Usage on macOS

Dear Firefox Support Team, I am writing to report an issue I’ve been experiencing with Firefox on my MacBook Air (M3, 8GB RAM). Recently, Firefox has been becoming unresp… (read more)

Dear Firefox Support Team,

I am writing to report an issue I’ve been experiencing with Firefox on my MacBook Air (M3, 8GB RAM). Recently, Firefox has been becoming unresponsive quite often, and the Activity Monitor shows significantly high memory usage. For context, I typically have two Firefox windows running simultaneously, with approximately 5 tabs open in each window (10 tabs total). This is when I notice the performance degradation and high memory usage.

To help you investigate, I’ve attached:

  • A screenshot of the memory usage in Activity Monitor when Firefox is running.
  • A screenshot of the extensions currently enabled in Firefox.

I am open to suggestions, such as disabling or removing certain extensions if they might be causing conflicts. However, I wanted to report this issue first to understand if this is a known problem or if there are optimizations planned for Firefox on Apple Silicon Macs.

Let me know if you need additional details, such as Firefox version, macOS version, or specific steps to reproduce the issue. I’d be happy to provide any information that can help resolve this.

Thank you for your time and assistance. I look forward to your response.

Best regards, Hemant

Archived 1 160

Firefox hangs on starrting on Mac

Firefox 147.0.4 (aarch64) "hangs" for 30 seconds to 1 minute when I launch it on my MacBookPro (OS Tahoe.26.3). Itwon't open the simple web page I have Firefox set to ope… (read more)

Firefox 147.0.4 (aarch64) "hangs" for 30 seconds to 1 minute when I launch it on my MacBookPro (OS Tahoe.26.3). Itwon't open the simple web page I have Firefox set to open when it launches -- and I can't navigate to any other web pages. When I try to interrupt, I get an Apple spinning beach ball until finally, Firefox opens that first page.

After working with Apple tech support, I have disabled a number of content barrier Extensions in Firefox-- which Apple tech support felt might have been causing this behavior. Nothing works. And I hesitate to run Firefox without some of them.

I tried deleting my Firefox user profile from my computer, but all that did was prevent Firefox from opening at all.

How can I stop this?

[edited email from community support forum]

Open 1 189

Every since I updated my MacBook Pro to 142.0.1 (aarch64), Firefox locks up & has to be Force Quit

Every since I updated my MacBook Pro M1 Max chip to Firefox 142.0.1 (aarch64), Firefox locks up & has to be "Force Quit" & restarted almost every day. Please upd… (read more)

Every since I updated my MacBook Pro M1 Max chip to Firefox 142.0.1 (aarch64), Firefox locks up & has to be "Force Quit" & restarted almost every day. Please update the app ASAP so I don't have to convert to Google Chrome. Thank you!

Archived 4 140

Unable to open settings immediately after starting in Troubleshoot Mode

When I launch Firefox in Troubleshoot Mode and try to open the Settings page (about:preferences) right away, Firefox becomes unresponsive. This issue does not occur when … (read more)

When I launch Firefox in Troubleshoot Mode and try to open the Settings page (about:preferences) right away, Firefox becomes unresponsive. This issue does not occur when Troubleshoot Mode is off.

I'm using Firefox 140.0.4 on macOS Sequoia 15.5.

Archived 2 150

Mac Scaling Issues Moving from Clamshell mode to Built in Retina Display

Hello, for quite some time I have been encountering an issue where the scaling of browser elements gets broken when I unplug my Mac from its dock/external display and the… (read more)

Hello, for quite some time I have been encountering an issue where the scaling of browser elements gets broken when I unplug my Mac from its dock/external display and then being using Firefox using the built in Retina display. This only impacts Firefox and renders Firefox completely useless until I quite Firefox and reopen it. It impacts all open Firefox windows. The attached screenshot explains it better.

Firefox 146.0 (aarch64) MacBook Pro 16-inch, 2023 macOS 15.5 (24F74)

Any ideas?

Archived 3 178

Firefox for Mac is eating up all my resources

When I launch Firefox, it uses well under 1GB in memory, but then it starts to increase that amount quickly in just a few minutes and gets up to 50+GB, causing error mess… (read more)

When I launch Firefox, it uses well under 1GB in memory, but then it starts to increase that amount quickly in just a few minutes and gets up to 50+GB, causing error messages to pop up repeatedly until it uses all resources and locks up my computer. I have updated my MAC OS and the Firefox app, uninstalled the Firefox App and still have the same problem.

Please help

Open 1 40

FIREFOX BROWSER FREEZES

I use a Mac running macOS Sequoia 15.7.2. Each time I attempt to login to https://music.amazon.com, Firefox freezes which then requires me to quit Firefox and restart. … (read more)

I use a Mac running macOS Sequoia 15.7.2. Each time I attempt to login to https://music.amazon.com, Firefox freezes which then requires me to quit Firefox and restart. Therefore, I need to use another browser to access the site. What is the solution to this issue?

Solved Archived 3 300

Firefox consuming all my RAM.

MacOS, M2 2023, fully up to date firefox. Sometimes I'm using firefox and it just stops loading pages, internet is fine. Other browsers work. I look at my activity monito… (read more)

MacOS, M2 2023, fully up to date firefox.

Sometimes I'm using firefox and it just stops loading pages, internet is fine. Other browsers work. I look at my activity monitor and nearly 100% of my 32GB of ram is being consumed by various firefox processes. A lot of those processes seem to be associated with youtube. This problem usually, but not always, is resolved by restarting firefox. But this shouldn't be happening. I have a lot of tabs open sometimes, but it's not that excessive. And most certainly not 32GB worth and preventing my computer from doing a google search.

If there's a debugging thing I can do to post system logs, let me know and I'll post them next time this happens. I'll be away from my computer until early July, so around that time.

Open 40

Website freezes when I clear browsing data

I updated to version 153.03. As a habit, before I close firefox I always clear browsing data. After the update, when I click "clear" to clear browsing data, the website f… (read more)

I updated to version 153.03. As a habit, before I close firefox I always clear browsing data. After the update, when I click "clear" to clear browsing data, the website freezes every time. I have to force quit to exit the website. I have macbook, sequoia 15.7.3

Open 1

Remove AI features from this browser

Please stop adding AI to your browser. It is making it slower and is a data privacy concern for me as well as many others. If you do not remove them I will be switching b… (read more)

Please stop adding AI to your browser. It is making it slower and is a data privacy concern for me as well as many others. If you do not remove them I will be switching browsers. AI is not only bad for the environment, it does not even do the features you want it to do correctly. Please remove AI from firefox, i have been using this browser for years and would hate to leave because you refuse to remove AI features nobody asked for.

Archived 1 608

firefox is hot garbage with macos tahoe update

Your browser dead ass just doesn't respond when I click on it. I have a new mac mini 4 and have the latest update for firefox. it's absolute dogshit to be honest. I'm luc… (read more)

Your browser dead ass just doesn't respond when I click on it. I have a new mac mini 4 and have the latest update for firefox. it's absolute dogshit to be honest. I'm lucky if the browser lets me click on anything, eg., bookmarks, add-ons, history are nonfunctional. Also my tabs on the browser get squished together and superimposed such that 2-3 separate tabs appear as though they are one tab. I have never had an issue like this before when using firefox. I don't encounter the issue with safari or chrome, but I don't like those browsers. Do you have insight as to why firefox mozilla is suddently ass?

Archived 1 300

internet gets slower and slower

My internet browsing gradually gets slower over time. By the end of a day or a couple of days, it is unusable. The problem isn't bandwidth. A speed test shows that throug… (read more)

My internet browsing gradually gets slower over time. By the end of a day or a couple of days, it is unusable. The problem isn't bandwidth. A speed test shows that throughput is absolutely normal. It's the browser response to navigation. ie clicking a link, typing a URL into address bar, etc. and having to wait minutes for the page to start loading.

If I quit the browser and re-open, everything goes back to normal.

Any ideas what might be the problem?

Archived 1 120

Tabs overlapping and other weird stuff

I am having trouble with Firefox that's very odd: the tabs keep overlapping and I am not able to click on links. It keeps happening randomly and I have no idea why! I've … (read more)

I am having trouble with Firefox that's very odd: the tabs keep overlapping and I am not able to click on links.

It keeps happening randomly and I have no idea why!

I've attached a screen grab so you can see what I mean.

When this happens I have to close down the tabs in question and then reopen them.

Never had this issue before.

Archived 1 160

Firefox won't let me leave application by clicking in a different window.

After installing Firefox 150, clicking on a window for a different application does not make that application active. Firefox is not letting me leave! I can switch by go… (read more)

After installing Firefox 150, clicking on a window for a different application does not make that application active. Firefox is not letting me leave! I can switch by going to the sidebar and choosing a different application. None of the other applications exhibit this behavior. MacOS 26.3.1

Open 1 60

FireFox frozen by Mac OS Virus warning.

Sporadically over the past year, a virus warning, purportedly from Apple, has locked my FireFox screen. I must Force Quit to unlock FoxFire. See images. Is this a scam? … (read more)

Sporadically over the past year, a virus warning, purportedly from Apple, has locked my FireFox screen. I must Force Quit to unlock FoxFire. See images. Is this a scam?

Open 1 150

Is there a new MacOs bug about Firefox refusing to minimize/relinquish control?

This new issue is puzzling: Normally, on MacOS, when you minimize an app that's currently running and occupying the desktop, say by clicking the orange button at top lef… (read more)

This new issue is puzzling:

Normally, on MacOS, when you minimize an app that's currently running and occupying the desktop, say by clicking the orange button at top left or by clicking another app, its menu would disappear from the top toolbar and other apps could then be invoked. Clicking that app icon again would restore it to the screen and its menu would again be on the top toolbar.

But Firefox has stopped allowing that behavior: Now, when I try to minimize Firefox, while its screen minimizes (revealing the desktop underneath), its menu remains on the top toolbar. It is as if Firefox refuses to let go of the controls. So, while you can see the other icons on the desktop - say file folders - they are unresponsive to clicks and do not open when you click them, as if Firefox is not letting you access File Manager.

Furthermore, you can still access these desktop file folders, but only by opening the finder using the bottom toolbar menu, not by clicking the file icons directly.

For what it's worth, all menus are still responsive (bottom toolbar, top toolbar, apple menu), just nothing that's on the desktop responds when Firefox is still running, despite being minimized.

Open 1 60