When you disable add-ons they don't get "lost".

Try the Firefox SafeMode to see how it works there.
A troubleshooting mode, which disables most Add-ons.
(If you're not using it, switch to the Default Theme.)

• You can open the Firefox 4.0+ SafeMode by holding the Shft key when you use the Firefox desktop or Start menu shortcut.
• Or use the Help menu item, click on Restart with Add-ons Disabled... while Firefox is running.
  

Don't select anything right now, just use "Continue in SafeMode."

To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shft key) to open it again.

If it is good in the Firefox SafeMode, your problem is probably caused by an extension, and you need to figure out which one.
http://support.mozilla.com/en-US/kb/troubleshooting+extensions+and+themes

When you figure out what is causing that, please let us know. It might help other user's who have that problem.

Thanks so much...that all sounds very reasonable. Will follow instructions and see what happens...and then let you know.

OK - the-edmeister...I just tried it in safe mode...same thing - no senders visible. I'm sure it's some sort of Yahoo mail setting...why would that suddenly happen when I didn't change anything on my settings. Yahoo has been such a pain lately (not just for me)...so I'll finally cave in and start using my gmail account more.

Thanks again for the tips!

Elli

please open my yahoo mail with firefox

I am having a similar problem. My Yahoo mail account does not load correctly and of course does not work. I can use a different browser and Yahoo mail works normally.

I tried running Firefox in Safe mode but the situation does not change or improve at all.

Can someone offer any other suggestions?

Thanks, Paul T.

Try this - Clear your browser cache <- click it, it's a hyperlink

If needed, delete the site's cookies.
Right-click the page, choose View Page Info > Security > "View Cookies"

Spinning your wheels, I think, I have the same problem in Safari ... I also have to search every e-mail address I don't have memorized because auto-complete no longer works (but will occasionally - go figure). Although this seemed to pop after the last Firefox update I think it was coincidence because the issues also appear in Safari. Yahoo Help suggested removing add-ons and plug-ins, which I did for both browsers and restarted - no luck. I'm at a loss ....

Hey thanks edmeister; clearing my browser cache' did the trick! The link you gave me had really good instructions.

Best Regards, Paul T.