Sorry to hear about these issues. Do you eventually get crashes, or do you have to "kill" Firefox yourself to end the freezes? Firefox usually collects data about crashes, but for freezes, unfortunately, we have to troubleshoot using a process of elimination.

Here are two initial suggestions:

(1) For the unresponsive script errors, a common culprit is the protected mode feature of the Flash player plugin. It has security benefits, but seems to have compatibility issues on some systems. There is a hidden setting to disable it:

(A) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(B) In the search box above the list, type or paste flash and pause while the list is filtered

(C) Double-click the dom.ipc.plugins.flash.disable-protected-mode preference to switch its value from false to true.

This might not take effect until all Flash has been unloaded for a few minutes, or you close Firefox.

(2) Test in Firefox's Safe Mode to see whether that makes any difference to performance. It's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

Thanks for your quick reply. I will have time this afternoon (Central Standard Time) to work on it.

You will hear back from me by the end of the day.

If the above does not help,

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

Doing that fancy tweak to Flash helped somewhat -- I was still getting scripts, but not the same scripts. So I started Firefox in self mode and have just spent and hour browsing with no problems.

Thank you!!!

Hi WonderingWoman, the Safe Mode test covers many things at once, so I'm not 100% sure which is helping you, but you could consider these:

(1) Hardware Acceleration

Safe Mode disables the use of some features of your graphics card/chipset. Firefox may have compatibility issues with the driver software for some of those.

Since hardware acceleration improves the appearance of fonts and animations, we generally recommend checking your computer manufacturer's website to see whether any graphics card/chipset driver updates are available for your system. This article has some links and further suggestions: Upgrade your graphics drivers to use hardware acceleration and WebGL.

Alternately, if you don't notice problems with fonts and animations, you could try disabling Firefox from using hardware acceleration when it returns to normal mode. You can set that here:

"3-bar" menu button (or Tools menu) > Options > Advanced

On the "General" mini-tab, uncheck the box for "Use hardware acceleration when available"

This takes effect the next time you exit out of Firefox and start it up again not using the Shift key.

(2) Extensions

Safe Mode doesn't disable all Add-ons, but it does disable extensions. You may want to review your list and consider whether any are nonessential and could be disabled for a day or two to test whether that helps with the video issues.

Because Safe Mode automaticaly disables extensions, you might not be able to do this until exiting Firefox and starting up again normally.

Open the Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then, if in doubt, disable.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

@ jsher

The problems with Firefox not responding are back, although I have disabled hardware acceleration and the only add on i have is adblocker plus. Also, Firefox was slow to open before and has gotten slower.

Perhaps you already have seen these, but just in case, anything useful here:

• Firefox hangs or is not responding - How to fix
• Quick fixes if your Firefox slows down
• Firefox is slow after updating to Firefox 38

I think I have read everything Firefox has up, but I will check those links.

I take it back. I have not read everything. This will take a while -- like days.