Hi, here's a brief checklist because I'm not sure of your situation: (1) Does the extension appear on the Add-ons page, Extensions panel, as Enabled? You can view, disable, and manage extensions on the Add-ons page. Either: * Ctrl+Shift+a (Mac: Command+Shift+a) * "3-bar" menu button (or Tools menu) > Add-ons * type or paste '''about:addons''' in the address bar and press Enter/Return In the left column of the Add-ons page, click Extensions. On the right side, find the "Manage Your Extensions" heading. ''If there is at least one extension before the next heading -- "Recommended Extensions" -- please continue:'' Then scan down that list. Is the extension listed in the Enabled section? If it is listed in the Disabled section, click the slider switch to enable it. If it is not listed at all, then that is the problem, we need to figure out why it's missing after installation. I guess the installation wasn't successful, but I don't know why not. (2) Do you use private browsing mode? If you switched Firefox to full-time/automatic private browsing, your extensions need to be enabled for private windows or Firefox will not run them. More info in this article: [[Extensions in Private Browsing]]. (3) Is the toolbar button or context menu item nonfunctional? Usually, the developer needs to troubleshoot this kind of problem. We can mention where to look for error messages if that could lead to a faster resolution, but we are a bit limited in how much we can dig into the operation of proprietary add-ons.