I think this is different than using Firefox's built-in command: right-click > Save Image As... If you are using Yahoo! mail, many users have had problems with downloading attachments in the past few weeks. Yahoo! has moved accounts around among its servers and sometimes when you use an old bookmark, you are not redirected to a fully functional server. To work around this issue, access you mail one of these alternate ways: * From Yahoo home page: https://www.yahoo.com/ * From the My Yahoo page: https://my.yahoo.com/ * Generic mail redirect: https://mail.yahoo.com/ You may want to log out and log in again in through one of the above links. If you get to a server that works, change out your old bookmark for the new address. ---- 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: orange Firefox 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" * Alt+t (open the classic Tools menu) > 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?