Is it this one: https://addons.mozilla.org/firefox/addon/ether-metamask/ ? The reason I ask for confirmation is that users have reported being scammed by fake wallet extensions, so I think it's important to confirm '''exactly''' which one you are installing. '''Some reasons an extension toolbar button might not appear even if the extension is enabled on the Add-ons page:''' ''Permissions'' If you are browsing in a private window but the extension does not have permission to run in private windows, the button may not appear. Please check the following article for more information on this issue and enabling your extensions to run in private windows: [[Extensions in Private Browsing]]. ''Customization Issues'' You'll likely want to open the Customize tab for these. See: [[Customize Firefox controls, buttons and toolbars]]. (1) Check whether the button has "overflowed" to the >> button near the end of the bar. In Customize, there's a box for that. You can drag icons from that box back to the bar. (2) Check whether the button has been removed from the toolbar and is among the available buttons on the Customize tab. There are in no particular order, unfortunately. (3) Reset your toolbar layout if you suspect it has become corrupted. You can use the "Restore defaults" button along the bottom of the tab. Any progress so far?