I recently got some web pages prompting that Flash was not installed. I am running Safari 11.0.3 on macOS 10.13.3. I followed the link to download the latest version (22.214.171.124) of installation package. After restarting Safari, still no success. I found some instructions to check in Safari Preferences > Web Sites and change the settings for Adove Flash Player Plugin.
But is does not show up in the list of plugins despite several attempts to reinstall it.
I have tried uninstalling it, then clear the two folder in Library as described in the memo, then rebooting, again with no success.
I just noticed that the installation progress regularly till around 50% then skip to the end to claim that the installation was complete. Is there any installation log file I could check to see if something is wrong during installation.
It works OK with Chrome, but not in Safari or Firefox.