What do you want to save?

If you are viewing a PDF, you will want to save using the controls offered by your viewer. For example:

• Firefox 19 PDF Viewer: Use the "download" button on the right side of the toolbar
• Adobe PDF plugin: Use the "save" button on one of the toolbar (floating toolbar that appears if you mouse toward the bottom center of the page, or classic toolbar that appears if you press the Esc button)

Is that on the right track?

Maybe save a photo or a document to the desktop. I am not talking about a pdf file.

I see. The menu generally refers to the "top level" content, so there are some other methods you might need to use.

If the photo is displayed by itself, for example, the URL ends with .jpg, then "Save Page As" will save the photo.

For photos in a page, try one of these:

• right-click > Save Image As
• right-click > View Page Info > Media tab, then select the image in the list and use the Save As button
• Tools menu > Page Info > Media tab, then select the image in the list and use the Save As button

For documents, it would depend on how they are displayed. For email attachments or other links, you could try right-click > Save Link As.

Are we getting closer?

I can't recall ever seeing a more globally powerful Save As on the File menu in Firefox. Maybe you had an add-on that enhanced the menu? If it only recently disappeared, e.g., after an update, you could check on whether the extension was disabled and see whether an update is available. Your disabled extensions cluster in a grayed out area at the bottom of this tab:

orange Firefox button (or Tools menu) > Add-ons > Extensions category