If it works in Firefox Safe-mode then disable all extensions (Tools > Add-ons > Extensions) and then try to find which is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

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

In Firefox Safe mode these changes are effective:

• all extensions are disabled
• the default theme is used (no persona)
• userChrome.css and userContent.css are ignored
• the default toolbar layout is used (localstore-safe.rdf)
• the Javascript JIT compiler is disabled
• hardware acceleration is disabled

• plugins are not affected
• preferences are not affected

Good tip to close and start firefox after each change. I was going to do the process of elimination, but the close and restart tip was one I'd not factored in. Thanks for the tip. I'll try it and let you know which add-on was causing problems with Twitter. I've been using Firefox in "safe mode" since the middle of last week.

Without "safe mode" new tabs do not open by using ctrl T, or clicking on the "+" sign, or clicking on the new tab option under "file."

I have all the same problems and I've tried all of the mentioned solutions but none seem to work. However *magically* it temporarily works after resetting firefox and opening Twitter right after, but if I reload or open another tab with twitter it goes back to its problematic state. Help! I don't want to have to use another browser.

I disabled add-on's one at a time until I found the culprit. It was and Avery.com add on for downloading templates. I really can't say that was the problem because I had intermittent successes before I attempted the disabling of add-ons. But it's working now.

I have been having this problem too, i was using Firefox 18 yesterday as i have been for a very long time without having any problem then out of know where my twitter doesnt work so i tried updating to Firefox 19, still have this problem, i uninstalled my Firefox browser and went to internet explorer and my twitter works fine with internet explorer, but i would rather be using Firefox, i just reinstalled Firefox from scratch and twitter still doesn't work, i don't have any add on's so it looks like i might just have to switch back to internet explorer until someone can tell me how to fix this problem/ any ideas and no i don't have any add on's at all thanks Brett

If you don't have any add-ons or extensions that could be causing the problem, perhaps it could be a settings issue. I have firefox 19 (with Ghostery, NoScript and other add-ons) and twitter works fine for me. The only way I could replicate the problem experienced by brettmcleod is by disabling javascript in the browser. Twitter needs javascript. I would check that this setting in options is enabled - other than that I'm stumped, sorry.

thanks, i will check it out tomorrow, i have been using internet explorer all night and i am sick of it already, Firefox is so much more user friendly, i just don't understand how everything was fine for the past 6 months and then all of a sudden it doesn't work, but i will check to see if JavaScript needs an update or something, thanks for your reply, i will let you know how i go with it. cheers Brett

A temporary solution I've been using so far is to use firefox with private browsing.

If it works in Firefox Safe-mode then disable all extensions (Tools > Add-ons > Extensions) and then try to find which is causing it by enabling one extension at a time until the problem reappears.

Close and restart Firefox after each change via "File > Exit" (Mac: "Firefox > Quit"; Linux: "File > Quit")

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

In Firefox Safe mode these changes are effective:

• all extensions are disabled
• the default theme is used (no persona)
• userChrome.css and userContent.css are ignored
• the default toolbar layout is used (localstore-safe.rdf)
• the Javascript JIT compiler is disabled
• hardware acceleration is disabled

• plugins are not affected
• preferences are not affected

thanks for that, yes it all works with private browsing :)) I will use that until i track down the problem. off to work will try the other options tonight, thank you all for your replies cheers Brett

Is Private Browsing the disk cache and the cookies from the regular browser session are disabled.

If clearing cookies doesn't work then it is possible that the cookies.sqlite file that stores the cookies is corrupted.

Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete other present cookie files like cookies.sqlite-journal in the Firefox Profile Folder in case the file cookies.sqlite got corrupted.

• http://kb.mozillazine.org/Cookies
• https://support.mozilla.org/kb/Deleting+cookies

Unfortunately cor-el that didn't help. I deleted the cookies.sqlite and the other cookies._____ files then restarted and nothing has changed. I should also mentioned that if I sign out and sign in again the page is completely functional until I refresh.