The window that popped up on my screen was from the app (extension) itself letting me know that there was something wrong with it in Firefox. It was fine in Safari. So I believed it and clicked "fix" and it did. Whew!
The final piece of the puzzle...my puzzle, anyhow:
I clicked on the extension and it said there was a problem with my extension in Firefox. I don't even use it in Firefox so I turned it off. (Emphasis added)
I assumed that the pop-up popped up within your browser...Safari, since you don't use the extension in Firefox, but it apparently just popped up...independently of either browser.
Have you got the both the Safari and Firefox versions of the extension?
