Is that extension enabled in the Addons Manager?

If it is enabled, try Evernote support for help with their extension. https://evernote.com/contact/support/

I assume it is enabled. When I go to the Add-ons Manager, it is listed with options for Options, Disable and Remove.

Yes, if it offers "Disable" it is enabled. You are looking in the Additional Tools and Features palette after clicking on Customize in the "Open menu" panel, aren't you?

Beyond that, I don't know what to recommend besides to see Evernote for help about the lack of the toolbar button in their extension. Not like it is a surprise though, a recent User Review mentioned that user couldn't find that button either, but I didn't view all the Reviews to see how many users mentioned that or when it may have went bad - just the latest version or before.

You can open the Browser Console (Firefox/Tools > Web Developer) and check if there are error message that mention this extension.

• https://developer.mozilla.org/Tools/Browser_Console

Edmeister: Thanks. Yes, I am looking at the Additional Tools and Features palette. I noticed this afternoon that LastPass, another extension which has been enabled is not showing either. They do show on my Windows 7 machine. I will have to be sure they are running the same version of Firefox. Will report back later.

can find your add ons here about:addons

Now it's a problem with two extension buttons gone missing? Probably a 3rd extension screwing things up due an incompatibility. I call it "doesn't play well in a group" - taken from some of my primary grade report cards in the 1950's.

See troubleshoot issues using the Firefox SafeMode.

Or you can start disabling extensions until you find out which one is causing both those "buttons" to disappear. Or provide a list of your installed extensions and maybe one of us might recognize the culprit. Help > Troubleshooting Information and use "Copy to clipboard" and then paste that info to Pastebin. http://pastebin.mozilla.org/ Give us the ID URL after doing the "paste".

I refreshed Firefox and disabled all the available extensions. Then I installed the two extensions I needed. They installed with icons on the menu bar and I was able to get into both. The other extensions are also enabled. I think your solution worked. Thanks for your patience.