Here are a couple questions: (1) Does it make any difference if you access Yahoo! mail through the general "redirector" or through the Yahoo home page? (In some cases if you are using an old link/bookmark, Yahoo doesn't always redirect to the correct new server.) * http://mail.yahoo.com/ * http://www.yahoo.com/ (2) Have you noticed any issues with secure sites lately, such as Firefox not trusting their certificates or having to make exceptions? ---- More generally: When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site. (1) Bypass Firefox's Cache Use Ctrl+Shift+r to reload the page fresh from the server. Alternately, you also can clear Firefox's cache completely using: "3-bar" menu button (or Tools menu) > Options > Advanced On the Network mini-tab > Cached Web Content : "Clear Now" If you have a large hard drive, this might take a few minutes. (2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either: * right-click and choose View Page Info > Security > "View Cookies" * (menu bar) Tools Page Info > Security > "View Cookies" In the dialog that opens, you can remove the site's cookies individually. Then try reloading the page. Does that help? ---- In case one of your extensions is involved, could you test Yahoo! mail in Firefox's Safe Mode? That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: [[Troubleshoot Firefox issues using Safe Mode]]. You can restart Firefox in Safe Mode using either: * "3-bar" menu button > "?" button > Restart with Add-ons Disabled * (menu bar) Help > Restart with Add-ons Disabled Not all add-ons are disabled: Flash and other plugins still run After Firefox shuts down, a small dialog should appear. Click "Start in Safe Mode" (''not'' Reset). Any difference?