Crashes or other problems with certain multimedia content in Firefox (such as YouTube videos and Flash animations or games) can often be resolved by performing the steps in these Knowledge Base articles:

• Flash Plugin - Keep it up to date and troubleshoot problems

• Adobe Flash plugin has crashed - Prevent it from happening again

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Thank you for your quick reply. As I stated all my software and plug-ins are up to date and running fine. And I did eventually try and disabling of hardware acceleration and/or protected mode, to no avail. If you have any other ideas or suggestions please let me know. (And again it seems to be site specific, I play plenty of other flash games and content without any issues at all). TY.

What site are you having problems? Please give us a link to check.

Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies
  Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences<Enter> in the address bar.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Then restart.

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

http://kb.mozillazine.org/Error_loading_websites

https://support.mozilla.org/en-US/kb/websites-look-wrong-or-appear-differently

My copy/paste into the reply field resulted in odd formatting.

Thank you for your reply. I use CCleaner to automatically flush my cache, cookies and temp files; but I did it manually (as per instructions) just in case, but with no change.

The problem persists while running FF in safe mode. I have turned of hardware acceleration in the FF settings, in the Flash settings (by right-clicking in the flash window itself). Neither one of those options had any effect either individually or together whether in safe mode or not.

If you want to check the issue yourselves; go to lumosity.com (you'll have to sign up, but you can throw it any garbage info and email). It will give you a 3 game “fit-test”; game 2 “train of thought” shows the issue quite well. Whenever you click the button to change the direction of a switch; the entire game freezes momentarily. The effect gets more and more pronounced the more trains are on the screen, or if you hit many buttons in quick succession. If you refresh the page before the game ends it will let you replay it (so you dont have to keep re-signing up to get to it. What I did in between settings changes).

Firefox is running the latest version 38.0.5, all my add-ons and plug-ins are updated and current. These should not be large or complex flash games; and I've played many other games on other sites without any issue. Also the site and games play fine on the exact same laptop through IE (which has been my work-around for now). Unfortunately I first began noticing the problem shortly after both FF and lumosity did an update (and I updated Flash when I updated FF) So I cant pin down where the problem “should” lie, and have so far been unable to get to the root of it. Lumosity's response (after a few of the cookie and other simple ideas); was to switch to Chrome. I would prefer not to do that, but if I cant get it working on FF I may have to jump ship.

Thank you again for any help you might be able to provide. I'm still hopeful for an answer.

Note, please do not put a 'space' at the beginning of a sentence. That results in special formatting that you see above. And it's hard to read.

Looks much better now, thank you.

Thank you for your reply. I use CCleaner to automatically flush my cache, cookies and temp files; but I did it manually (as per instructions) just in case, but with no change.

The problem persists while running FF in safe mode. I have turned of hardware acceleration in the FF settings, in the Flash settings (by right-clicking in the flash window itself). Neither one of those options had any effect either individually or together whether in safe mode or not.

If you want to check the issue yourselves; go to lumosity.com (you'll have to sign up, but you can throw it any garbage info and email). It will give you a 3 game “fit-test”; game 2 “train of thought” shows the issue quite well. Whenever you click the button to change the direction of a switch; the entire game freezes momentarily. The effect gets more and more pronounced the more trains are on the screen, or if you hit many buttons in quick succession. If you refresh the page before the game ends it will let you replay it (so you dont have to keep re-signing up to get to it. What I did in between settings changes).

Firefox is running the latest version 38.0.5, all my add-ons and plug-ins are updated and current. These should not be large or complex flash games; and I've played many other games on other sites without any issue. Also the site and games play fine on the exact same laptop through IE (which has been my work-around for now). Unfortunately I first began noticing the problem shortly after both FF and lumosity did an update (and I updated Flash when I updated FF) So I cant pin down where the problem “should” lie, and have so far been unable to get to the root of it. Lumosity's response (after a few of the cookie and other simple ideas); was to switch to Chrome. I would prefer not to do that, but if I cant get it working on FF I may have to jump ship.

Thank you again for any help you might be able to provide. I'm still hopeful for an answer.