Many site issues can be caused by corrupt cookies or cache. In order to try to fix these problems, the first step is to clear both cookies and the cache. Note: This will temporarily log you out of all sites you're logged in to. To clear cache and cookies do the following:

1. Click the menu button , choose History, and then "Clear Recent History...".
2. Under "Time range to clear", select "Everything".
3. Now, click the arrow next to Details to toggle the Details list active.
4. From the details list, check Cache and Cookies and uncheck everything else.
5. Now click the "Clear Now" button.

Further information can be found in the Delete browsing, search and download history on Firefox article.

Did this fix your problems? Please report back to us!

Thank you.

It's a new profile, but I'll do that anyway. Just went ahead and cleared that, same issue.

The URL I'm on is:

https://secure.hulu.com/signup?src=login-form&driverid1=login-form&driverpage=welcome&drivertype=nav-element&upselltype=1

And I click "Login".

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

I think that the issue is probably caused by the uBlock addon. Please try disabling this addon to see if the issue goes away. If the issue goes away with it disabled, please add the websites with issue to the whitelist.

I disabled uBlock, no luck. Same issue. Attached screenshot.

Have you tried running Firefox in safe mode, as FredMcD suggested? If so, was the issue still present?

Can't, see my other questions. Safe Mode is basically dead for me, it either crashes (I provided a crash log) or it never connects to any site.

Sometimes websites will not display correctly when Firefox's hardware acceleration is enabled. Can you please try disabling the hardware acceleration, by doing the following:

1. Click the menu button and select Options on Windows or Preferences on Mac or Linux
2. Select the Advanced panel and then the General tab
3. Uncheck Use hardware acceleration when available
4. Restart Firefox and see if the problems persist

Let us know if this fixes the issue.

Turned off hardware accel, restarted Firefox, same issue.

Can you please try disabling all of your addons using the addon manager page? This will help to ensure that there are no conflicting addons causing the issue.

It is important that you disable the addons from about:addons, not using any other method provided by the addon developer. This will ensure that the addons are completely disabled will not be causing any issues.

If the issue is present with addons disabled, you can enable your addons again and let us know.

If the issue is gone, one of the addons is causing the issue and you should enable them one at a time, until you can determine which one is causing the issue.

Only got 2 addons, but yep. It was LastPass. Disabling that and it looks fine now. Great... guess I'll contact them.

Thanks! :)

Glad to hear that you discovered what the issue is. Unfortunately, since Mozilla is not responsible for addons, there is nothing more than we can do on our end. So please contact the addon developer and they will take a look into the issue. Thanks for contacting Mozilla support.