Here are the screenshots:

It looks like you are missing CSS files.
Make sure that you do not have security software that is blocking files.
You can also try to disable IPv6 in Firefox as a test.

• http://kb.mozillazine.org/Error_loading_websites#IPv6

Try to reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files if this happens.

• Press and hold Shift and left-click the Reload button.
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (MAC)

Thanks, how do I get the CSS files back where they should be and what software could be blocking it?

I do run the Ghostery, Adblock, and Better privacy extensions, but have been for years without problems, and when I disable them, I still get these page load errors.

Thanks.

You will have to reload pages that are corrupted and do not display properly.

Note that extension like Adblock Plus and Ghostery can block content and you always need to check that is it isn't working properly, but that would be consistent and can't be cured by reloading unless you unblock such content.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

cor-el,

Thanks for the suggestions. I tried them all and they did seem to reduce the incidences of the loading/rendering errors a wee bit, but I still have the problem and it still occurs daily.

From the beginning, restarting Firefox and then going back to whichever website didn't display properly has fixed the problem temporarily. Is it possible that Firefox is intermittently writing a corrupt cache or temp file of some sort which is then cleared on a restart? What might be causing that?

Any ideas for a solution would be still be greatly appreciated as neither Safari nor Chrome allow for the same level of privacy control as Firefox.

Thanks!

More Screenshots:

You can check the Net log in the Web Console (Web Developer > Web Console;Ctrl+Shift+K) console to see if there are errors with retrieving files.

You need reload the web pages and bypass the cache to refresh possibly outdated or corrupted files from the server.

• Press and hold Shift and left-click the Reload button.
• Press "Command + Shift + R" (MAC)

See also:

• https://developer.mozilla.org/en/Tools/Web_Console

As you can see below, there are plenty of CSS warnings with regard to file retrieval. And given the error descriptions it makes sense that pages look the way they do. I took the screenshot right after the browser failed to load a couple of pages correctly.

The question remains as to why this is happening. Bypassing the cache to reload pages does seem to work (as does restarting the browser), but both of those options are not really solutions to the problem.

You can hide the CSS and JavaScript errors and leave only the Net Log and Net Errors selected by clicking the associated buttons.
Then you can see if all files are retrieved successfully (GET: response: 200 OK).

You can try to disable IPv6.

• http://kb.mozillazine.org/Error_loading_websites#IPv6

You can try to reset (power off/on) the router.

Firefox 18 appears to have resolved the problem. Since its been out I haven't had any of the persistent rendering errors. Very occasionally a webpage will render with the errors for a fraction of a second, but then quickly corrects to the proper display.

Edit: And a couple of days later the same old problem reared its ugly head again upon going to the Amtrak site, which was really a mess.

Anyone have any idea how to stop this?

I am having the same problem. For me it does not disappear when I restart firefox. In fact I reinstalled OS X to get rid of it and now, 1.5 months later, I got it again.

Here is my system model: iMac model-Ident: iMac11,2 prozessor: Intel Core i3, 3,06 GHz system version: Mac OS X 10.6.8 (10K549) kernel version: Darwin 10.8.0

I am running FF 18.0.2 with the following addons: Adblock Plus 2.2.2 DownloadHelper 4.9.13 DownThemAll 2.0.15 FireGestures 1.6.19 NoScript 2.6.4.4

I tried renaming my FF-folder in ~/library/appsupport and restarted FF with virgin settings but the problem is still there. @NewishMacGuy, Any similarity with my system? I am surprised the problem reappeared after my reinstall but it does not seem there are many people out there who have it.

If you use extensions (Tools > Add-ons > Extensions) like Adblock Plus or NoScript or Flash Block that can block content then make sure that such extensions aren't blocking content.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Problem occurs in safe mode too, I also tried deactivating hardware acceleration, none of it helps.

I just downloaded the latest executable FF and ran it - no problem. I will post later whether this is a permanent or temporary relief. edit: temporary.