What homepage are you referring to? YouTube loads on my Firefox has no lags. Sounds like you go internet ISP provider issue if it resumes playback without issues. And no one two Firefox setups or Addon are and runs the same unless you can test in Private Mode window browsing runs without issue and if so that means you got Addon caused problems. And to turn all off and then turn on/off each playing Youtube to isolate the Addon issue and remove it and find a better Addon to use.

If you use extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) that can block content (Adblock Plus, NoScript, DuckDuckGo PE, Disconnect, Ghostery, Privacy Badger, uBlock Origin) always make sure such extensions do not block content.

• make sure your extensions and filters are updated to the latest version
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

Firefox shows a purple shield instead of a gray shield at the left end of the location/address bar in case Enhanced Tracking Protection is blocking content.

• click the shield icon for more detail and possibly disable the protection

You can check the Web Console for relevant-looking messages about blocked content.

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

You can try these steps in case of issues with webpages:

You can reload webpage(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the Cache and remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Settings).

"Remove the Cookies" for websites that cause problems:

• Settings -> Privacy & Security
  Cookies and Site Data: "Manage Data"

"Clear the Cache":

• Settings -> Privacy & Security
  Cookies and Site Data -> Clear Data -> [X] Cached Web Content -> Clear

• https://support.mozilla.org/en-US/kb/clear-cookies-and-site-data-firefox
• https://support.mozilla.org/en-US/kb/how-clear-firefox-cache

Start Firefox in Troubleshoot Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration or if userChrome.css/userContent.css is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Troubleshoot Mode start window

• https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems

• https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop
• https://support.mozilla.org/en-US/kb/smartblock-enhanced-tracking-protection
• https://support.mozilla.org/en-US/kb/trackers-and-scripts-firefox-blocks-enhanced-track

Thanks cor-el for your reply. For me a I can try a few of your recommendations at a time. I will try disabling "use recommended performance and hardware acceleration". I will also try "the remove cookies from you tube". After those possible fixes I can try use "Firefox in safe mode". I will get back with you after I try those possible fixes. Thank you, cor-el. Please be patient with me here. I don't want to over whelm myself with fixes and get my self into trouble in doing so. I'm not exactly a computer wizard.

cor-el, I disabled hardware acceleration and using recommended performance settings. No effect in helping the problem. I removed cookies on both you tube and my homepage, MSN. That also made no difference. I went to Firefox in safe mode and to extent it seemed to help. But it really didn't help the you tube issues I mentioned. When I finally went to another browser,(Brave), the problems went away. So I know the problem is my browser Firefox. That being said, where can we go from here cor-el? The problem is the browser and not my computer. What other things can I try with Firefox to either eliminate the problem or at least improve, especially you tube when I use it. The video and audio that shudders when viewing is annoying. I don't experience that with the browser Brave. I also notice when I'm viewing you tube, in Firefox, if I have another tab open while you tube is operating, the audio and video is really bad, but close that tab and things get noticeably better. I don't experience the same issue with Brave? Hopefully you may have some other suggestions, cor-el. I've been using it for many years and prefer to keep using it. Thank you, cor-el.

Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove your Firefox program files and then reinstall Firefox. This process does not remove your Firefox profile data (such as bookmarks and passwords), since that information is stored in a different location.

To do a clean reinstall of 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 mozilla.org (or choose the download for your operating system and language from this page) and save the setup file to your computer.
2. After the download finishes, close Firefox.
   • Windows: Click the Firefox menu , then click "Exit".
   • Mac: Click the Firefox menu at the top of the screen, then click "Quit Firefox".
   • Linux: Click the Firefox menu , then click "Quit".
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows: (Note: Check both folders.)
     • 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.

More information about reinstalling Firefox can be found here.

WARNING: Do not use a third party uninstaller as part of this process. Doing so could permanently delete your Firefox profile data, including but not limited to, extensions, cache, cookies, bookmarks, personal settings and saved passwords. These cannot be easily recovered unless they have been backed up to an external device! See Back up and restore information in Firefox profiles.

Your data should be safe as, starting from Firefox 31, the uninstaller will no longer let you remove user data. More info here

Hi Infinity, thank you for you reply, it is appreciated. I took your advice and performed step # 1. Frankly I didn't know how to save the set up file to my computer as was suggested? But nonetheless, I closed the Firefox I was using. Before going onto step # 3, I thought I would try the "new" Firefox I just installed without deleting the installer as is suggested in step # 3. Yes, I was jumping the gun but I was curious and was worried about getting my Firefox browser screwed up by going any farther. But, after I opened the "new" Firefox I just installed, the problems I was having with you-tube were completely gone! Opening my home page was also faster than before. So, it appears, at least for now, my problems have been resolved? My question is now, do I really need to go any further with the instructions you suggested? Using step # 3, deleting the installer and step # 4, reinstalling Firefox? From what I can tell with my limited computer skills, I already reinstalled my "new" Firefox, so maybe it just is a matter of the deleting the installer issue in step # 3? Just not sure what to do going forward, Infinity. I would very much appreciate your opinion and suggestions. Thank you once again, Infinity!! It very much appears you solved my problems with Firefox. Look for forward to your reply.

Hi there, I'm glad to hear that! Continuing onto step 4 shouldn't take longer then 3 minutes (and that's considering you have a pretty low-end computer). Deleting the installation files would prevent the browser from confusing the old files from the new ones and may also prevent the same problem from occurring again, so I highly suggest you to do so (you might have to reinstall the browser again if you accidentally delete the wrong files). If you can, please do mark the previous message I sent as the chosen solution so that others could find the solution as well. Thanks!

Hi Infinity, thank you for your reply. I think I understand your comments. But, concerning step # 1, "and save the setup file to your computer". How do I save that file to my computer? It would appear I would need to do so to proceed? Maybe give instructions as to how do so? Some what confused by that being it seems my computer and browser work fine now? In so far as step # 3 deleting the installer, "Delete the Firefox installation folder, which is located in one of these locations, by default:"

   Windows: (Note: Check both folders.)
       C:\Program Files\Mozilla Firefox
       C:\Program Files (x86)\Mozilla Firefox 
How do I locate where to find those folders on my computer, Infinity? Yes, I know probably rather rudimentary question but it would help. Being you seem it is important to delete the installer.

"If you can, please do mark the previous message I sent as the chosen solution so that others could find the solution as well." I thought I did that, Infinity? If not explain how to do so? Again, thank you for your help AND patience, Infinity.

Hi there, "Save the setup file to your computer" simply refers to downloading the file, I apologise for the confusion. In order to delete the previous installation folders, you'll need to:

1. Open Windows Explorer (by pressing the icon in the taskbar, via Start or using the shortcut, WindowsLogo+E).
2. On the side menu, press "This PC".
3. Select the local disk. If you have multiple, select your main one where you install programs.
4. After locating the Local Disk, enter it and then select "Program files".
5. Enter "Mozilla Firefox". This is the first file you want. Please delete the required files. If the "Mozilla Firefox" folder isn't here, please go to the next step.
6. If the required folder isn't there, use the bar at the top to go back to "Local Disk".
7. Now head into "Program Files (x68)"
8. Delete the requires files. If the files aren't here, go back to check "Program Files" and double check both files.

Regarding marking the solution, please mark the question that I sent - I believe that you've marked your response to my solution by accident. To do so, simply head to the response you made to my first post in this thread (the post with the green "Chosen solution" and to the right there should be a button saying "Undo". Press that button. After that, head to the previous post (or my first post) and mark that as the solution instead.

Hi Infinity, thank you for your reply. I did as you asked about the solution to the problem issue. Hopefully I got it right this time. I will try your deleting Firefox installation instructions and see how that works and get back to you. That is why I clicked on the needs more info tab, just in case something went wrong and I can contact you again and not be lost in the Firefox help forum? Maybe I won't need any more info though. Thank you, Infinity for your help AND patience.

Hi Infinity, Frankly, I just can't locate what you suggest to delete Firefox installation. " Open Windows Explorer (by pressing the icon in the taskbar, via Start or using the shortcut, WindowsLogo+E).

   On the side menu, press "This PC".
   Select the local disk. If you have multiple, select your main one where you install programs.
   After locating the Local Disk, enter it and then select "Program files".
   Enter "Mozilla Firefox". This is the first file you want. Please delete the required files. If the "Mozilla Firefox" folder isn't here, please go to the next step.
   If the required folder isn't there, use the bar at the top to go back to "Local Disk".
   Now head into "Program Files (x68)"
   Delete the requires files. If the files aren't here, go back to check "Program Files" and double check both files. 

First, when I click on the Windows icon I don't see a This PC option anywhere? Maybe there's another way for me to select local disk which seems to be the objective? I can access a "my computer" and see hard disk drives (2) and OS (C:) for one of the disk's. It shows 333 GB free of 439 GB. Is this the disk your talking about? If so, when I double click on it, it shows a lot of file folders that seem to have codes? But nothing to show Firefox. Let alone Firefox installer? It seems I'm trying to delete the Firefox installer, right? So, maybe you could help here in somehow directing me another way to delete the Firefox installer I used to refresh Firefox? Maybe I was in the right area with my hard disk drives? But again, when I opened the disk drive I saw nothing in the file folders that pertained to Firefox? Can you help, Infinity? You certainly thought a good idea to delete the Firefox installer. Thank you, Infinity.

Hi there, There appears to be some misunderstanding. When I meant WindowsLogo+E, I meant to hold down the windows button on your keyboard. However, it seems like you've located the Local Disk (C:) anyhow, but you'll have to find either "Program Files" or "Program Files (x68)", depending on your device architecture, although they should both be there.

Hi Infinity,

   Thank you for the reply. Your comment, " However, it seems like you've located the Local Disk (C:) anyhow, but you'll have to find either "Program Files" or "Program Files (x68)", depending on your device architecture, although they should both be there." 

When I open the local disk for info at what is there, I find many file folders. But all are in a code of some kind. But, I just looked at the date associated when they were created and I see nothing associated very recently, like 01/2023. So, evidently what I am looking for is not there.

I guess to simplify things?, where else can I possibly find the Firefox files, program files (x68) or Firefox program files? in my computer. 

Again, to make sure I'm on the right track here, I want to specifically delete the Firefox installation folder (wherever that might be located) but not delete, or uninstall Firefox itself and start over again by installing the latest version like I just did a few days ago? Trying to just delete the installer like you strongly suggested. I do appreciate your help and patience. Thank you again, Infinity.