Of course you should update to Enterprise Manager 13.4 (or later) after the 12th of January 2021. Ok, so you don’t want to or you can not do this at this moment or I need it NOW!
There are two things happening here. 1) Adobe implemented a kill-switch that you can not use Flash anymore after the 12th of January and 2) your browser stopped supporting/running Flash.
This blog post is about issue 1. The ‘kill-switch’.
Adobe’s Flash “Enterprise Enablement”
What?! Yes, you can still run Enterprise Manager with Flash after the 12th of January 2021, but you need to do something called “Enterprise Enablement” and have sites be placed on the Flash Allow List.
Read about it in the Adobe Flash Player Administration Guide for Flash Player 32.
Create a Flash Allow List
Be warned, outdated Flash is unsafe…! Enable it for EM only (AllowList it).
Flash implemented a kill switch, so you can not use Flash anymore after the 12th of January. Luckily you can allow site to still run Flash!
Create the following file mms.cfg as Administrator and save it in C:\Windows\System32\Macromed\Flash\ and C:\Windows\SysWOW64\Macromed\Flash\ .