Simple solutions to fix Flash crashes when using Firefox

We review each new stable Firefox release here on Ghacks Technology News, and one recurring theme that we come across is that at least some users report issues with Adobe's Flash Player after they have updated to the latest version of Firefox.

While many users do not experience any issues, some do and it can be a frustrating experience, especially if you do not really know where to start troubleshooting the issue to resolve it.

Both Firefox and Flash are complex programs, which means that there is not a single solution that fixes the issue for all users experiencing crashes or hangs.

firefox crash flash player

The following list may help resolve the issues that you are experiencing. Lets get started.

Make sure Flash is up to date

flash plugin up to date

If you are running an older version of Flash, you may experience crashes or hangs that are resolved in newer versions. This is not always the case, and it can very well happen that upgrading to the latest version causes the issues to appear on your system for the first time.

Generally speaking, it is better to run the latest Flash version than an outdated version. The reason here is mostly security, as older versions are vulnerable to attacks that got fixed in the updated versions.

Check to see if your Flash version is up to date on Mozilla's Plugin Check website.

You can download the latest Flash Player version from Adobe.

If that version is causing issues for you, you may want to try a beta version of an upcoming version of Adobe Flash instead.

What I do not suggest is to downgrade due to the security implications that come along with it.

Enable Click-to Play

flash click-to-play

The Flash plugin is enabled by default in Firefox, which means that it can be used by any website you load in the browser.

By enabling click-to play, you prevent that Flash can be used on all sites but the ones that you allow it to run on. This prevents the loading of Flash ads, videos, or other Flash contents on the majority of sites, which in turn improves stability.

  1. Type about:addons in Firefox's address bar and hit enter.
  2. Switch to Plugins using the left sidebar.
  3. Locate Shockwave Flash here and switch from "Always Activate" to "Ask to Activate".
  4. If you have multiple Flash plugins here, do the same for them. In fact, do this for all plugins that are configured to always activate unless you have configured them this way.

You can whitelist specific sites easily, here is how that is done.

adobe flash allow

  1. Tap on the Alt-key and select Tools > Page Info from the menu that opens up at the top of the Firefox window.
  2. Switch to Permissions here and locate Activate Plugins Adobe Flash here.
  3. Change from "Use Default" to "Allow".
  4. This allows the website in question to run Adobe Flash whenever it is needed.

Use one browser to play Flash contents, and Firefox for the rest

Okay this may not work for all users or be desired by most, but if you experience a lot of hangs or crashes in Firefox that are related to Flash, you may want to consider using a different browser to play Flash contents.

This works well if you only visit a couple of sites that require Flash, maybe sites like YouTube, Kongregate or Armorgames for example.

The best browser in my opinion for this on most systems is Google Chrome, as it comes with a native version of Flash. If you use Windows 8, you may also use Internet Explorer as it comes with its own native Flash version as well.

If you only use YouTube, switch to HTML5 video

html5-player

HTML5 Player

If YouTube is your only destination on the Internet that requires Flash to play videos, you may want to switch to HTML5 video instead to avoid the crashes and disable Flash Player in your browser or even uninstall it.

Most videos will work just fine if you make the switch, but some may not, so keep that in mind.

To switch, go here and click on the request the HTML5 player button.

Disable hardware acceleration

disable hardware acceleration

Flash uses hardware acceleration which is designed to improve performance when Flash Player is being used on your system.

It can cause issues on the other hand, and one way to find out if hardware acceleration is responsible for that, is to disable it to see if crashes or hangs stop or continue.

  1. Go to this official Adobe Support page.
  2. Right-click the Flash icon on that page that is displayed, and select Settings.
  3. Switch to the first tab in the settings window that opens up (named Display) and disable "Enable hardware acceleration".

Disable Protected Mode

Protected Mode was added to Flash Player 11.3 and later on Windows Vista and newer versions of the Microsoft Windows operating system.

It has been designed to improve the security of the system by limiting the impact of attacks launched from malicious Flash files.

You can try and disable Protected Mode on your system to see if it resolves the issue. We have published an extensive guide on how to do so here.

Disable Plugin-container.exe

plugin-container

It used to be easy to disable plugin-container.exe, the file that is run whenever you run plugins such as Flash. I have published a guide on how to disable the feature in newer versions of Firefox.

It requires the creation of a new user or system environment variable. Check out the full guide here.

Clear Windows Prefetch files

flashplayer prefetch

While I was not able to test the following solution myself, some users have reported that it resolved all Flash issues that they were experiencing on their PC.

The user who came up with the solution suggested to clear two Windows prefetch files every 15 minutes:

  • C:\Windows\Prefetch\flashpl*.pf
  • C:\Windows\Prefetch\PLUGIN-CONTAINER*.pf

You can either do so manually, or create a task in the Windows Task Scheduler instead to do so automatically for you.

I suggest you try the solution manually first to see if it resolves the issue. If it does, implement an automated solution. The user who posted the solution has created a script that you can run for that purpose.

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Responses to Simple solutions to fix Flash crashes when using Firefox

  1. Nebulus February 5, 2014 at 9:36 am #

    Thanks for the advice. However, there are two issues with it that people should be aware:
    1. Sometimes using an older version of flash instead of the latest one fixes the problem. This happened to me: I had to downgrade Flash in order to stop some freezes related to it. However, I recommend this only as a last resort because of the security vulnerabilities that it might create.
    2. Deleting prefetch files does nothing related to Flash or Firefox. These are files created by Windows and used by Windows. You can use Process Monitor and see that Firefox/Flash doesn't touch those files (neither read, write or other operations).

    • Martin Brinkmann February 5, 2014 at 12:46 pm #

      In regards to the prefetch fix; I have not tried it, and cannot say if it works or not. From what I read, some users have claimed that it resolved all their issues with Flash, Firefox, and crashes or hangs.

  2. Dwight Stegall February 5, 2014 at 9:59 am #

    I'll sure be happy when there are more plugins. :)

  3. Lanny February 5, 2014 at 12:33 pm #

    Excellent article. Thank you!

  4. paul(us) February 5, 2014 at 1:35 pm #

    After upgrading to the latest Adobe Flash beta version the new release of Mozilla Firefox version 27 was working like a charm again.
    Still is it strange that established firms like Adobe and Mozilla are not working together at all it seems, this because when the one has a upgrade it seem they not check or there product will work with the outer his product. Like I wrought " Strange maybe even ferry strange!"

    • Paul(us) February 5, 2014 at 2:12 pm #

      Update on main story from earlier today.

      I thought that working with main new configuration was working like a charm again.
      Was I mistaken they adobe flash beta and firefox 27 crashed after a few hours on a relative easy site (www.ghacks.net).

      • Martin Brinkmann February 5, 2014 at 2:30 pm #

        I do not have that many pages that use Flash, only when a video is embedded.

  5. Swarup February 5, 2014 at 4:43 pm #

    Thanks Martin for this useful tips. I just update my settings.

    I switched to chrome due to frequently crash.

  6. Q February 5, 2014 at 8:35 pm #

    Adobe Flash Player has been somewhat buggy on Firefox for a long time. I had submitted bug reports to Mozilla via Bugzilla to have them resolved, but they were labeled as WONTFIX. There are some important functionality problems that Mozilla unfortunately does not seem to dedicate much resource to (like fixing printing layout).

    I have found that issues with Flash Player crashing and (more importantly) Firefox browser instability can often be attributed to the plugin container ("plugin-container.exe"). Disabling it would generally result in greater stability of both the browser and the Flash Player plugin.

    I have never had to set a Windows Environment Variable to disable the plugin container. It should be noted that the plugin container of some version series of Firefox (like Firefox 17 series) could not be disabled in Windows. This problem was both intentionally created by and corrected by Mozilla. I can confirm that both Firefox 10.0.12 and Firefox 24.1.1 both can have their plugin containers disabled on Windows XP Professional with Service Pack 2. The following information describes the preferences to set to disable the plugin container in these versions of Firefox:

    // Disable using separate process for plug-ins (using plug-in container)
    // General handling (Firefox default is true)
    user_pref("dom.ipc.plugins.enabled", false);
    // Disable to existing overrides (Firefox default is false)
    user_pref("dom.ipc.plugins.java.enabled", false);

  7. Xmetalfanx February 6, 2014 at 1:17 am #

    As usual, thank you for the very useful information

    What I have noticed (while the version numbers of each are different, I mean a fairly recently updated version of Firefox and/or Flash ) is that it is VERY inconsistent and I have only had it happen while in Youtube. 1/2 the time there are crashes ....usually only happening (if at all) when I move the video's progress slider on my own (if i let the video play, then no crash ... sometimes If it's say a 30 minute video and I saw the first 15 minutes or so already, I move to the point where I left off)

    ANYWAY, THE POINT I wanted to bring up is that (while the versions numbers may be slightly different) ... no matter what Desktop Environment I pick (Linux users will know what I mean) .. I have NOT HAD IT CRASH in Linux Mint 16 (to be exact on which version I am on) ... If its going to crash it ONLY happens for me in Windows.

    -Xmetalfanx

  8. Dave February 6, 2014 at 5:43 am #

    Removed 'No Trace' add-on. Now Firefox doesn't crash.

    • Xmetalfanx February 6, 2014 at 10:18 am #

      I HAD the plugin too and noticed the frequency of the crashes going up (something needed that its blocking?) ... after (for other reasons removing it, i am at least noticing less crashes too

      I am NOT SAYING thats a bad addon... just that its probably blocking something and that is whats causing the crash .. interesting

      -Xmetalfanx

    • Xmetalfanx February 6, 2014 at 10:20 am #

      Assuming someone else doesn't beat me to figuring it out, I should install Notrace again and see if I spot what (what Notrace is blocknig perhaps) may be the cause ... this may not be the reason "everyone" is having this issue, but it may have been my cause ... I will look into it

  9. Larry February 6, 2014 at 9:12 pm #

    Unfortunately, FireFox has backed itself into technical corner dilemma. I am no longer able to use it as a browser, which is my preference. A crash two weeks ago and my click on restart brought me to a very strange unrecognizable FireFox browser with all my bookmarks, extensions, set ups gone for good. In the past I had been able to get everything back, but since the last update all this has occurred and terminated my access.

    I uninstalled it, and tried reinstalling, but continue to get a message that group manager will not permit me to run the setup. I tried everything I could find online as the fix for it, with glowing promises that it would take care of it, even one I got right here on this tech site. Nothing. More of the same. I've tried accessing the MS program .exe files recommended to fix the group manager settings and I get a message that there is "no such file".

    So, now I am back to IE 11 which is not my choice. Too often all the well-intention updates, upgrades, and the like send us into periods of wasting hours just to get back to normal after we use them. Personally, I am weary with it and do not intend to spend my life in recover from updates mode.

  10. MM February 9, 2014 at 7:09 am #

    The prefetch cleaning did it for me, ty!

  11. T. Brooks Web Design May 3, 2014 at 12:20 am #

    For months I've been getting the dreaded "Adobe Flash has crashed" notices in Firefox and have had to frustratingly use an alternate browser just for Flash content. I tried different versions of Firefox and Flash, disabling hardware acceleration, disabling protected mode, and clearing prefetch files. Nothing worked.

    Then I read on one message board to try uninstalling Windows update KB2840149. I did it and restarted the computer, and IT WORKED! I gave it a few days to make sure it's stable, and it's been fine. And uninstalling that update hasn't caused any other issues. KB2840149 is a "security update for the Windows file system kernel-mode driver" and it applies to Windows 7, Windows Vista SP2, and Windows Server 2008. http://support.microsoft.com/kb/2840149

    To uninstall a Windows update, go to Windows Update (you can search for it from the Windows Start button), click "View Update History" on the left, and then "Installed Updates" at the top of the next screen. Give it a minute or so to show all the updates, then look for the heading "Microsoft Windows". Under that heading look for KB2840149. I don't think there's an easy, automated way to search for it. The update came out in April 2013, but mine updated in December 2013 since that's when I bought my new computer. When you find it, right-click and select "Uninstall". Then restart your computer, and (hopefully)... Voila!

    If you're running Windows 7 or Vista SP2 it's worth a try. Good luck!

    Teri Brooks
    T. Brooks Web Design, LLC
    http://www.tbrookswebdesign.com

  12. ringsteel May 28, 2014 at 3:12 am #

    WTF is the point?????? IF you have a shit load of work around?????? SERIOUSLY!!!!

    The average user is NOT a techie come on people get your head out of your ass!!!

    Every browser has issues but IE and Chrome do function without crashing or locking up or looking for a computer programmer to look under the hood and tweak it.......What Mozilla is doing is pushing away users as myself that no longer have any interest in tweaking shit just want to get on line conduct business and move on....So FF if this keeps up and the best you can do is tell us WONT FIX or the form letter thank you for your feedback...blah...blah...blah well then you folks can pound sand and go by the way of the Commodore 64..........very frustrated with your crappy forums.....I have 4 devices laptop 8 gig ram, desktop 16 gig ram, tablet 16gig and S4 with 16 gig and the tablet and phone have NO ADD ONS....yet all 4 will run the other browsers just fine so you shitty forum of blaming lack of ram is just technical obfuscation and maybe you would be better serve to be a spokesperson for the politicians....OK....I'm done and yes feel better after 2 weeks of living and working being a 2 hour drive and needing a safe dependable browser to conduct on line business FF 29.0.1 has driven me away...To the viewer thank you for allowing me to vent it has been very very very irritating indeed.....good night folks and for those that have the patience of a saint....my hat is off to you and salute you all for the temperance of trying to get this once fine browser running again...

    • Cindy d. August 29, 2014 at 3:56 am #

      I agree with ringsteel. I am just an average end user. I've been having theses freezes and I searched for a solution. Some of the solutions were ridiculous: changing pre-fetch codes or editing lines of code in the browser. If I make a mistake, then what? I have a mess! Who has time to do this kind of stuff? I just want my computer to work! All these problems are making me want a Mac. The price is high, but it seems you get a quality product. I don't want to tinker with the software. It's not what I got a computer for. Time to dump Mozilla I guess and try Chrome.

  13. DCS October 16, 2014 at 12:31 pm #

    The main solution to all the terrible IT issues is to force all the software companies to make and develop software that is actually compatible with everything. Not to mention the quality of software is so bad, how humans can marvel at crap technology is quite arrogant and beyond me.

    What we have at the moment is very poor quality software that is unable to live up to the quality all the software companies claim. Other issues are, if they actually made a quality piece of software which no one currently does other than "Military Applications", whether Windows or Adobe, then we would also not need so many updates.

    Personally I think the updates are purely there to eventually slow your computer down in order for you to be forced to go out and purchase new equipment or a new computer, for the greed of the likes of Microsoft who obviously do very well from you purchasing a new computer. Think about it, makes complete sense to me, and if you think about it logically, this is exactly what the software companies want you to do in order for them to continue to make money.

    If they made quality software in the first place we would not need updates almost everyday, would we?. Do you think "Military Applications" need updating every effing day, due to an error with the flash media or another error with Microsofts lame quality software, as a few examples?, answer to that NO, why, because they have quality software, were as we end up with the afterbirth that the software companies make their massive profits from. Every time an update goes on, what does it add to your computer, think about it?. It adds more strain to your computer, eventually slowing it down so much that the computer is unable to handle the data, yes?. It is not the hardware being the problem, it is the lack of quality software, and unfortunately software companies all of them, but more specifically Microsoft want your money and will force you to spend out as they will force you to update your computer in order to f it up in the medium term, is basically what it amounts too.

    The only solution to all IT issues is to basically not use computers. Obviously this is unrealistic, but there is no solution I am afraid, other than to force them all to work as one. But this is Earth and humans do not know how to work as one. They know how to be greedy though :).

    Like banks, no solution to stop them from short selling and effing up our economy when it pleases them, as another fine example.

  14. Ken Bell October 18, 2014 at 2:51 am #

    I uninstalled Firefox than used internet explorer to reinstall it. Then I went to http://www.adobe.com and updated Adobe Flash software and the Adobe Flash Plug-In. Still had a problem. I then UNINSTALLED Adobe Flash Plugin. Problem solved. Computer runs great now. Actual problem is is with Adobe Flash Plug-in, not Firefox - Hope this helps.

    • FoaRyan November 11, 2014 at 4:59 pm #

      I've had problems with Flash on Windows XP, Windows 7, Mac OSX (multiple versions), and in Internet Explorer, Firefox, and Safari. It's been my experience that the "solution" is always "Update Flash and your browser." You'd think with years and years of updates we would have something fixed by now, but that's just me talking. Very good troubleshooting help on this website though.

  15. FoaRyan November 11, 2014 at 4:55 pm #

    Excellent information and advice on here. I hadn't thought about making Flash click-to-play. That can actually help in troubleshooting as well, since normally a user doesn't know when a Flash object has started playing. I'm going to give that a shot and see if it's any websites in particular causing my Flash player to act up.

    If anyone ever reads this and cares to answer, I have a serious question: Why does everyone say to disable hardware acceleration to help with Flash problems? This has been advertised by just about every flash help article I've ever read, dating back to the 1990s, it seems like. How is disabling something that is supposed to use your computer's built-in hardware going to improve things? And if it's that unstable, why haven't they removed the feature after over a decade of this problem? I have very little confidence in Adobe because of their continued, long-term problems with Flash. I can't think of many other places (besides the government) where you can get THAT MUCH wrong for THAT LONG and not face consequences.

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