Cannot save picture files

I cannot get a Windows file manager window to appear. When I click a website button that asks me to load a file, nothing happens. This problem also happens when I right-click a picture file on the screen and choose save-as - nothing happens. I just started having this problem yesterday. First, I tried resetting Firefox by the Troubleshooting screen. That worked briefly, but the problem came back later. Next, I tried creating a new profile. That too only worked for a short while. I can use other browsers without this problem. Firefox is up to date on my system.