First, please update to Firefox 17.0.1. Update Firefox to the latest release

Then, try to read Websites look wrong or appear differently than they should

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do not click the Reset button on the Safe mode start window or otherwise make changes.

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

I have the same problrem

I unchecked the "Tell websites I do not want to be tracked" option and normalcy was restored (Firefox 18.0.2 on Mac 10.8.2).

This fix did not work.

Still not able to replay to emails or create new emails. If this problem is not fixed soon I'll be forced to go to another web browser

Yahoo mail work fine when I use Windows Explorer. till this problem is fixed I'm switching it instead of FireFox

The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

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

i face the same issue for the past 1 year or so.. now i'm on the latest (20.0) and still have an issue..

i dont know why firefox gives useless upgrades.. it was stable only till 4.x then i was forced to upgrade to 11.. and have been facing this since then..

its INTERMITTENT.. some times "compose" works, while some times it does not.. some times forward doesnt work and if it does, it challenges you with a blank forwarded page and tests your patience trying to load a contact name.. im sure many would agree that the issues are count less

Firefox does not work with optonline webmail (their new version) and I cannot get to the older version. Optonline webmail worked once after I reset firefox, and once after I downloaded the most recent version of the browser. Please advise.

uninstall FLASH plugin for firefox, and yahoo mail will work like butter.

but i still miss the old multi tab enabled html format.. Ymail wants a change but it doesnt know whY!!

There's add-ons to add Yahoo functionality to Firefox. The following two are for sure worth having a look at:

• Yahoo! toolbar
• Yahoo mail notifier

See Find and install add-ons to add features to Firefox on how to get them.

Let us know if it helped.

PS: it works in my case (notifier, compose, the whole shebang). FX 21 on win 7 64

A general comment: the thread started with a question from a user, running FX 13. It makes sense - if there's no reasons not to - to update first to the latest version as described in Update Firefox to the latest release