Unfortunately nothing helped, Adobe Connect add-in is no longer launching in the virtual session. Then again uninstall and install the previous one. Then to manually uninstall the add-in, reinstall the latest one. The Mac Mini detected the USB installer and everything worked as expected. I suggested to enable pop up windows in Safari and Mozilla firefox, to clear cache from the browsers and try again. Subject: El Capitan on 2011 Mac Mini - Works Burned the El Capitan ISO to USB and booted up the Mac Mini while holding the Option Key (Alt-key). There is an article in adobe blogs I asked them to follow : (Though i'm not sure if the office update caused this). Then a day after the update, they reported that Adobe Connect opens directly in the browser and they are prompted to install the add-in again, which they did, but it's still not launching. One of the user installed the latest updated for office 2016 for MAC Released on Ma(the other 2 claimed they didn't install any update but probably it was done automatically). They used to work with adobe connect add-in under safari and firefox browser with no problem.

Some or many of the Application already installed may required update or upGrades to 64 Bit Versions.I have 3 users, all of them with MAC OSX El-Capitan 10.11.6 Suggest using Go64 to find 32 bit application before attempting the upGrade. Catalina, Big Sur & Monterey supports only 64 bit and there is no workaround. Notation - Mojave is the Last version to support 32 bit applications / extensions and Drivers. Make Time Machine Backup is very useful and can be used to Revert to Previous Working macOS OS X El Capitan - Technical Specifications MacOS High Sierra 10.13 hardware requirements I run Brave on my Mac Pro 1,1 when using it and everything works perfectly. MacOS Catalina 10.15 hardware requirements Chrome, Brave, Firefox, Opera are all still fully supported on El Capitan. Safari will open a redirect and open the Apple Store where the download can commence. For Best results use Safari to commence the download as Others may not work. With the above information in-hand - follow this How to get old versions of macOS and verify what version this computer Qualifies to install. Use About this Mac from the Apple Icon on Desktop - the required Information will be there. The Age of this computer will Govern what newer version of macOS it will Qualify to install. In so going - newer versions of Browsers would become available including newer version of Safari. This computer maybe Qualify to upGrade to macOS 10.15 Catalina.

Firefox for el capitan