I keep Flash installed because I need it for a few sites. But I can never use the regular Updater when Adobe interrupts me with their announcement.
It's probably some security settings, which are fine for everything else or maybe form directory permissions that I don't want to change. Anyway, There are some instructions on Adobe Forums but I got tired of re-opening the page, skipping what didn't apply, mistakenly downloading and running the Adobe offering and watching the "failed to install" message every single time I didn't use the alternate method!!!!
So, if anyone else ever has a problem installing this nearly useless piece of bloatware, print out or make a PDF of the following condensed and proven method to re-install Adobe Player flushware!
Info from:
https://forums.adobe.com/thread/1267823To start, Please follow the Uninstall instructions posted here: Uninstall Flash Player | Mac OS
(<
https://helpx.adobe.com/flash-player/kb/uninstall-flash-player-mac-os.html>)
DO NOT BOTHER DOWNLOADING THE REGULAR UPDATER FROM THE ADOBE SITE or the Update message you get on the computer! Get the NPAPI version at the site below!Download the offline installer posted at the bottom of the Installation problems | Flash Player | Mac page, in the 'Still need help' section of <
https://helpx.adobe.com/flash-player/kb/installation-problems-flash-player-mac.html)>
- There are two types Flash Player plugins: NPAPI for Firefox/Safari browsers, and PPAPI for Opera and Chromium-based browsers. Download the one(s) for the browser(s) you are using.
If it won't download directly, right click and "Save as"… and make note of the save location.
DO NOT mount the installer DMG or run the installer yet!Empty the trash.
Quit your Browser (Use Cmd+Q - Don't just close the window)
Go to: Mac HD/Library/Internet Plugins
Verify that the Flash Player.plugin and flashplayer.xpt files are not present. If it they are, trash them.
Go to: Mac HD/Library/Internet Plugins/PepperFlashPlayer
Verify that PepperFlashPlayer.plugin and manifest.json files are not present. If it they are trash them.
Go to: Mac HD/Library/Application Support/Adobe/Flash Player
Verify that the Flash Player Install Manager folder does not exist. If it does, trash the whole folder
Go to: Mac HD/Users/YourUserID/Library/Internet Plug-Ins
Verify that Flash Player.plugin file is not present. If it is, trash it.
Empty the trash,
again.
Reboot Shutdown and start up with the power switch.
Make sure the 'Reopen windows when logging back in' check-box is
NOT selected (This will "kill" all running processes)
Before launching any apps, mount the DMG and run the installer (double-click on the installer file to launch it).
During installation, when prompted for a password, this is the OS prompting for the password (e.g. your user Admin password),
not Flash Player.
BEFORE opening any Flash content, make sure Flash Player is enabled in the browser: Open a site like TS (where you should never see any direct Flash content) and check your browser prefs. Safari->Security->Internet Plug-ins/"Plug-in Settings..." You should now see a list of plug-ins with "Adobe Flash Player" as installed. You can add/delete sites and how you'll be notified if they present Flash content.
Now I'm sending a message to every site still using Flash and asking them to join the 21st Century!