Not clue anyone?

I tested the issue on my Firefox. I set a Twitter profile as the homepage and restarted Firefox. There was no major unresponsive time, but Firefox did lag for a second or two at first, which can be expected while it downloads the website's content.

For all of my Firefox testing, I use a clean profile that I created using Firefox's profile manager.

Does this issue occur every time that you navigate to a Twitter page after being on a different website or only when the Twitter page is setup as the homepage for the browser startup?

I do see that you stated you have restored the default profile. However, in my experience, many users tend to do this incorrectly. Therefore, can you please attempt to create a secondary profile using the Profile Manager? You can find steps on how to do this here.

To be honest with you I think there is a bug in this latest version of Firefox. I have started to post bug report each time my FF freezes or gives a debug error, I think something broke in the update which is what is causes so many problems.

Wesley Branton said

I tested the issue on my Firefox. I set a Twitter profile as the homepage and restarted Firefox. There was no major unresponsive time, but Firefox did lag for a second or two at first, which can be expected while it downloads the website's content...

There is a misunderstanding here. The problem occurs whenever I try to connect to a twitter account (i.e. highest parent node of a feed, designated on twitter using "@" -- @johndoe, @yourname, @whatever). What happens then is that my CPU usage skyrockets (up to 75%) and FF goes in the "not responding status".

I created a second profile as well, it does not solve anything. I think we can rule out the profile issue once and for good.

I wish I was able to bring more helpful data to the discussion. Given the heavy scripted nature of twitter, and given that this problem occurs on no other website as far as I know, I am convinced that it can be traced back to how the Firefox engine (on the 64bit version) handles twitter javascript. If you tell me how to, I could perhaps monitor the javascript execution pile and feed the results back to you?

I forgot that I am running the 32bit installation of Firefox. I just installed the 64bit version to test, but there is still no issue present on my end. To test, I tried visiting @Wesley_Mozilla and I also tried setting it as the homepage on startup.

Slower load times and even the occasional unresponsive warnings can be expected when loading a website like Twitter, since I is heavy on scripts and contains a lot of high resolution images. This issue will worsen if these pages are your homepage on startup. It can be caused by low quality or outdated hardware on your system or a slow network connection.

If you report this as a bug, our developers can take a look into the issue and see if there is a way to repair the issue or if it is an issue with the Firefox software. Please file the bug report onBugzilla.

Sorry for the inconvenience and hopefully someone on the Bugzilla team will have more information on the issue for you.

Have you tried reinstalling Firefox? Sometimes issues can be caused by invalid files in the Firefox program and can be repaired by reinstalling the software. Try following the steps 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.

Sometimes issues can be caused by invalid files in the Firefox program and can be repaired by reinstalling the software.

There can be a number of reasons that a file could become invalid or corrupt.

In some cases, another program makes a modification and damages the file. In other cases, the update/installation didn't work properly. And sometimes your computer just makes a mistake and damages the file.

It's very difficult to pinpoint what caused the issue and we can't really guarantee that you would able to prevent it from happening again.

Nevertheless, I'm very glad to hear that your issue was solved. Let us know if it happens again.