Action: what you should do
If you have Flash on your computer — any computer, Mac or Windows, laptop or desktop — remove it. Now.
Adobe announced in July 2017 that Flash was going away. Not fading to the background, but going away, forever. They even gave a date: December 31, 2020.
Once upon a time, Flash was a Big Deal. Introduced by Macromedia in November 1996, Flash was an audio and video technology that allowed developers to websites, games, and other multimedia content, complete with embedded scripts. Click on a button, for example, to fire a laser at an alien spaceship, or play the latest Tori Amos song.
By the time Adobe bought Macromedia in 2005, Flash was everywhere. And so were problems: the programming language behind Flash was complex, and many developers published poorly written animations or applications that didn’t work, or crashed the visitors web browser, or in many cases crashed the visitor’s computer. If that wasn’t bad enough, hackers used vulnerabilities in Flash to inject code that changed how Flash websites and applications acted, or even allowed a website to inject malware into the computer of a website visitor.
Monthly security updates could barely keep up with Flash vulnerabilities, but the real enemy turned out to come from a different direction entirely: Apple’s iPhone and iPad could not run Flash. Millions of websites and billions of dollars in development were off limits to iPhone and iPad users. Adobe tried to brush this off as a minor issue; there were over a billion installations of Flash on computers around the world. Who cares if it didn’t work on iPhones and iPads?
But people did care, and companies and governments were greatly concerned with the constant stream of Flash-based computer hacks. Companies and governments soon banned the installation of Flash on their computers. Google Chrome and Safari blocked the use of Flash, further restricting the scope of Flash-based projects.
The introduction of new web standards, including HTML 5, WebGL, and WebAssembly, reached the point that almost anything done in Flash could be duplicated using common, open standards rather than Adobe’s proprietary system.
What if I have a lot invested in Flash?
Write it off. There are ways to convert some Flash content to something more modern, but it is late in the game for such an effort, and it is difficult and time consuming.
How to remove Flash
gives Adobe’s view of the problem, and (in section 4 and 5) tells you how to uninstall Flash.
Can I just leave Flash on my machine and not use it?
In a word: no. Just having Flash on your machine can make your machine vulnerable to external attacks when you visit websites, or open up attachments in email, or open documents given to you.
To be safe, remove Flash from any and all of your devices. Now.