This generally doesn't work. Any time it pops up to log in, the page flashes in a popup window, immediately closes, and fails. I haven't found any workarounds that work - other than switching to Chrome whenever I need to use it. The most frustrating aspect of this is the browser extension is the _only_ way to generate virtual card numbers, for absolutely no reason at all. If I could just go to the Capital One website to do it instead then I wouldn't even be all that bothered that this extension never works.