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youtube videos lag/freeze on full screen when mouse is inactive, but only in firefox.

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I absolutely HATE IE, so I hope we can find a solution to my problem.

Pc info: Win 7 64 bit, 2.9 pentium with 4 gig ram video: radeon HD 3800

Three days ago I was infected by some malware. While i had it i could not watch videos on youtube in full screen unless i constantly moved my mouse. I uninstalled the malware and it didn't help. I reinstalled videos card drivers (even tried the new beta drivers), firefox, adobe flash, java 32 and 64 bit, and performed these steps:

I've reset Firefox, emptied cache in Firefox, and manually deleted all program temp folders I could find. Also, I have disabled all add-ons and plugins, and even ran Firefox in safemode. Nothing seems to work. There may be a few things I've forgotten that I've tried.

All Replies (13)

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Try Firefox Safe Mode to see if the problem goes away. Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

  • You can open Firefox 4.0+ in Safe Mode by holding the Shift key when you open the Firefox desktop or Start menu shortcut.
  • Or open the Help menu and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Once you get the pop-up, just select "'Start in Safe Mode"

If the issue is not present in Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one. Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before opening Firefox for normal use again.

Please report back soon.

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The issue is still present in safe mode. i am about to try these steps:

The problem still occurs in Safe Mode

If your problem persists in Safe Mode, it is not being caused by an extension, theme or hardware acceleration. Other possible causes could be plugins or changes made to Firefox preference settings, which are not disabled in Safe Mode.

   For additional troubleshooting suggestions, see Troubleshoot and diagnose Firefox problems, Troubleshoot issues with plugins like Flash or Java to fix common Firefox problems, and Reset Firefox preferences to troubleshoot and fix problems.
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ok i've tried every option that was suggested to no avail. (disabled every single add-on one at a time too.) anymore ideas?

Modified by Gizzard Snatcher

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Since the issue is still present in Safe Mode, we can say that it is not an issue with Firefox.

Do you have a fast internet connection?
When did this issue first occur?

Please check if all your plugins are up-to-date. To do this, go to the Mozilla Plugin Check site.

Once you're there, the site will check if all your plugins have the latest versions. If you see plugins in the list that have a yellow Update button or a red Update now button, please update these immediately.

To do so, please click each red or yellow button. Then you should see a site that allows you to download the latest version. Double-click the downloaded file to start the installation and follow the steps mentioned in the installation procedure.

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my connection is fine. i can watch videos on IE and chrome, even though i hate those browsers. In my post i said:

"Three days ago I was infected by some malware. While i had it i could not watch videos on youtube in full screen unless i constantly moved my mouse. I uninstalled the malware and it didn't help."

I think it is some issue with flash or something. I even swapped usb ports for my mouse and changed out my mouse.

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Malware can really cause a lot of issues.

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

  1. Download the latest Desktop version of Firefox from and save the setup file to your computer.
  2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
  3. Delete the Firefox installation folder, which is located in one of these locations, by default:
    • Windows:
      • C:\Program Files\Mozilla Firefox
      • C:\Program Files (x86)\Mozilla Firefox
    • Mac: Delete Firefox from the Applications folder.
    • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
  4. Now, go ahead and reinstall Firefox:
    1. Double-click the downloaded installation file and go through the steps of the installation wizard.
    2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

Please report back soon.

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Clean Reinstalled, and it works a little better actually now, but still the video freezes after 30 seconds and audio about 10 seconds later until i move the mouse. its very odd..

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Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen) as a test to see if that helps.

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well, in windows safe mode, it seems to play the video in full screen without the mouse moving, but while playing (normal or full screen) it either restarts the video several times or straight crashes the player.

Modified by Gizzard Snatcher

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It sounds like the malware mentioned in your original post, damaged either your graphics card or Adobe Flash Player.

Try a clean install of Adobe Flash Player. For more help on a clean install, consult Adobe.

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I've had this problem for some time, without being infected by virus. When my cursor is ON firefox, firefox will just randomly hang up. Like I'll click on a link, but nothing happens. Then, if I move my cursor at all, it wakes up and does what I ask.

With videos, they run a bit and then hang, or the video hangs but the audio continues for a bit. Moving my cursor makes the video continue. Or moving my cursor off the firefox and clicking to focus somewhere else makes everything work. Unfortunately, it is very hard to do this trick if you are watching a full-screen video. I have to make it full screen, use tab to get off focus, find another window to take focus, but then move that window almost off the screen so I can see the full-screen video.

I don't have this problem with any other browser -- it is like firefox messed up the interrupt code for the mouse pointer.

I have done safe mode, I've re-installed firefox, I've let it download the latest add-ons -- nothing makes a difference.

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I fixed my problem by switching to Google Chrome. I hope firefox can figure out what they screwed up, because I really liked the browser. But it was just driving me crazy, and I can't spend all my time "trying" a hundred different "solutions" none of which work.

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Sorry to hear that you are leaving the Firefox community.
We hope that you will return soon.
Sorry for any inconvenience that this issue has caused.