After Firefox updated to version 86 yesterday a couple of my users are being prompted to select what they would like Firefox to do with a PDF file each time they download one. They set it to open in Foxit Reader and checked the box to do it automatically each time but it always goes back to the default setting. I confirmed that the Application settings in Options is set to use Foxit Reader for PDFs and I even followed the troubleshooting step for this issue and renamed the handlers.json file. Also each time they try to download a PDF a prompt comes up asking for an admin password (see the 3rd image). These computers are on a domain, so the UAC prompt isn't unusual but we don't restrict them from being able to download files. But I'm having the same issue as well and I'm not on the domain, so I think this is more of a symptom then a cause. Is this a bug in the latest update? I was troubleshooting a printer setting issue for them the day before yesterday. Did some testing on my computer and theirs, got it worked out that Foxit works best for their needs when printing a PDF from a web app. Then yesterday afternoon they began to have issues where they couldn't print at all. I checked it out and all of our computers updated to Firefox v86 and everything is now working differently now in terms of handling PDFs. Thanks in advanced, Josh