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How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

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New User

How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

This happens maybe 30-50% of the time when I watch a video online, whether it be on YouTube or other streaming site. This usually happens when the video is at least 20 minutes long, and about 8-9 minutes in.

Looking at the Task Manager, my memory fills up to nearly its max (3.8-3.9 GB out of 4 GB) for a while before Firefox crashes. How can a video that is not very high definition take up that much physical memory space? After Firefox crashes, the RAM used immediately drops back below 1 GB.

Is this a Flash bug or a Firefox bug/leak? Or maybe my browser customization is at fault? It does not happen on Chrome.

11 REPLIES
Grand Master

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

Recent crashes of certain multimedia contents (this includes Youtube videos, certain flash games and other applications) in conjunction with Firefox are most probably caused by a recent Flash update and/or a malfunctioning browser plugin such as Real Player.

In order to remedy the problem, please perform the steps mentioned in these Knowledge Base articles:

Other, more technical information about these issues can be found under these Links:


Please tell us if this helped!

Grand Master

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

You should also try disabling FIrefox hardware acceleration and Flash hardware acceleration.

Mozilla Support Contributor

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

Thank you for uploading your settings. It seems you've reduced the amount of disk cache that Firefox can use. Could you try increasing that and see whether it has any effect on this problem?

orange Firefox button (or Tools menu) > Options > Advanced > Network mini-tab > "Cached Web Content" section


I wonder whether the video recorder/downloader extensions could be holding the stream in memory longer than usual. You could disable one or all of them, or test in Firefox's Safe Mode. That's a standard diagnostic tool to bypass interference by extensions (and some custom settings). More info: Troubleshoot Firefox issues using Safe Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the dialog, click "Start in Safe Mode" (not Reset)

Any difference?

Site Moderator

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

I think that Firefox is more likely to use the memory cache for such streamed media files.

What does it say about the caches on the about:cache page if you pause the playing after a few minutes?

Maybe you should consider to reset all prefs to cleanup and remove the obsolete prefs from older Firefox versions and possibly check the content of the user.js file as well.

New User

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

Hello everyone, I have not forgotten about you. Over time, I've tried all the relevant suggestions here, but I still have crashes. Here is a screenshot of what happened on the most recent crash. As you can see, memory crept up and stayed near max, and then Firefox crashed.

Currently, I have set my cache to 1 GB. My initial settings were not a limitation; rather, it was Firefox's smart cache management that automatically capped it around 350 MB. Hardware acceleration has been disabled both on my browser and for Flash. I've tried disabling the video download extensions, but it still crashed (I've re-enabled them since).

I haven't been able to test extensively with Safe Mode because these crashes seem to happen randomly and after a while of usage. But I suspect SM is safe from these crashes (especially since the other suggestions haven't helped). Assuming SM is the solution, how can I fix this problem during normal usage?

Thanks all.

2013-08-03-23-34-34-2a93fb.png 2013-07-24-20-09-50-19df52.png
Grand Master

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

There must be a addon interfering, or you need to disable hardware acceleration.

Mozilla Support Contributor

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

Safe Mode also disables Firefox's use of hardware acceleration for graphics. This is helpful when Firefox is not fully compatible with your graphic card drivers. You can manually turn that off for normal mode.

You generally need to restart Firefox in order for this to take effect, so save all work first (e.g., mail you are composing, online documents you're editing, etc.).

orange Firefox button (or Tools menu) > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

If you restart Firefox, is the issue resolved (or at least improved)?

New User

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

As mentioned, I have already tried disabling hardware acceleration for both Firefox and Flash (which did not work).

Barring any known solutions, it seems my only option is to test my extensions. It is a daunting task since the issue seemingly arises randomly, and I value the usage of my extensions. Hopefully I can get back to everyone eventually. Will report back on any solutions.

New User

Re: How to prevent physical memory filling up and crashing Firefox (22.0) when watching Flash-based videos?

To remedy the situation Firefox needs to fix their shit - full-stop.

This was never a problem - maybe it was once in a while, but now, nearly every time I watch a video it starts lagging, I restart theFox; no-problem... for a little while.

I can literally watch the flash plugin sapping my ram. With so many bitching about this, it is not a problem that computer users need to sort out, it's FF's problem, ffs.

I really, really don't want to use Chrome. (was on a forum the other day and was gobsmacked how many people admitted to tossing FF to the side and adopting Chrome BECAUSE of this issue.)

I've even been subjected to watching some vids on IE!! my word, what is the world coming to?