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Why is my Adobe Flash slow and laggy on Firefox, no matter what I try, but works just fine on IE7?

  • 4 replies
  • 131 have this problem
  • 25470 views
  • Last reply by jscher2000

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Whenever I watch anything requiring Adobe Flash (a YouTube vid, an anime episode on Crunchyroll, the latest episode of a show on RoosterTeeth's website, etc) on my Firefox (Version 22), it's horribly laggy and slow, with the picture AND sound lagging and 'skipping', and occasionally for YouTube the image will 'pixellate' and/or the sound quality will nosedive. According to the right-click option, my Firefox uses Flash 11.8. However, watching a vid on my Internet Explorer 7, which uses Flash 10.0, produces no such problems; the picture and sound are excellent. This problem has persisted ever since shortly after I first installed and began using Firefox earlier this year, when I (apparently mistakenly) accepted the offer to update my Firefox's Adobe Flash to Version 11 (it kept giving me "your Flash is outdated" messages that I had to click away to watch a vid, and that annoyed me so I wanted to make it stop).


This problem has been plaguing me for several months, and now that RoosterTeeth no longer supports IE7, I am unable to properly watch their new episodes. I have tried nearly everything - disabling Hardware Acceleration (with Firefox AND with Adobe Flash), having other tabs closed, several Flash updates as they become available since this problem's inception, upgrading my graphics driver, desperate prayer to God (and I'm a fairly secular man), EVERYTHING.


Could someone please tell me what is causing this months-running problem and how I could possibly hope to fix it?

All Replies (4)

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Did you post from the system that has the problem? (Your "More System Details" list shows Flash 11.7 instead of 11.8 for some reason.)

This is some standard guidance that addresses the most common issues with Flash in Firefox. I'm sure you've seen some of it before, but just in case:

(1) Make sure all recorders/downloaders that interact with Flash media are as up-to-date as possible, or disable them.

(2) Disable hardware graphics acceleration in Firefox and in Flash (I see from your post that you've done this part)

(A) In Firefox, un-check the box here and restart:

orange Firefox button (or Tools menu) > Options > Advanced > General > "Use hardware acceleration when available"

(B) In Flash, see this support article from Adobe: http://helpx.adobe.com/flash-player/kb/video-playback-issues.html#main_Solve_video_playback_issues

(3) Disable protected mode (Windows Vista/7/8)

See this support article from Adobe under the heading "Last Resort": Adobe Forums: How do I troubleshoot Flash Player's protected mode for Firefox?

Modified by jscher2000

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Try to delete the pluginreg.dat file in the Firefox Profile Folder and maybe addons.sqlite as well to reset the plugin registry databases.

See Re-initializing the plugins database:

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I just noticed I have a "Java Update Available". But:

1) I have no idea exactly what Java does (other than "something computery"), so I don't know if it would help any, and

2) I have in the past had a few very bad experiences with a nasty malware whose icon is a recolored Java logo, and am very worried that it's possibly infiltrated my computer's main Java thing, and trying to perform my waiting update may somehow trigger the catastrophe again.

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Websites can use the Java plugin to run a wide range of little programs. But you do not need Java to run Flash, so it's not immediately relevant.

Some users have reported interference between the Silverlight plugin and the Flash plugin on some sites. You also could try disabling Silverlight here:

orange Firefox button (or Tools menu) > Add-ons > Plugins category