Mostly trying to find out if anyone else is having this problem. I've been struggling with it on three machines. Go to Tools -> Add-ons -> Plugins tab -> Find Updates. This pops up a webpage that announces there is a security problem with an Adobe Plugin. It recommends an immediate update, but the update process is quite difficult. I hope that I've finally got it to work, but I'm trying to find out if other people have the same problem, if anyone else can explain what is going on, and whether or not my 'fix' is really adequate. The update process is long and complicated. I can only estimate that I tried about 25 times on three different machines. The process almost always seemed to run to completion, but when I checked again, it had not worked and the security vulnerability was still there and still needed to be fixed. What turned out to be the workaround was to close Firefox at a certain point in the update process. This was NOT clearly stated on the warning screen that came up at that point in the process. P.S. I did try to get help from Adobe, but their website is AMAZINGLY unhelpful. All that did was make me angry with Adobe, which surely wasn't their intention. However, at this point, if I had my druthers, I would absolutely never use any Adobe software. (I'm sure I'll feel better in a few days, but right now I hate Adobe.) (Additional annoyance was the constant request to install McAfee, which I absolutely do NOT want on any of my machines, even if I wasn't already required by company policy to use a different anti-virus product...)