See:

• http://kb.mozillazine.org/Flash

the kb article was NOT helpful - and I thought I am a fool that I cannot just click "download plugin" and have the plugin a minute later.

Three, four firefox restarts later it worked. The clue was somehow that there was a firefox task running or hanging with no user interface preventing the update being applied.

This leaves a bad taste - youtube definitively wants the newest flash because they switched to WebM and some new MP4 things which the old player couldn't do.....

and it's gettin' even worse - after finally having the flash working it didn't survive a reboot.

Today, same config but after a reboot FF12 "forgot" the flas h plugin. This sucks - but as it always happens, FF is a community product, Flash isn't. But these guys might say "fix the FF12" instead delivering software that integrates without any major probs into FF.

please Update Firefox to the latest release, since firefox 12 is no longer supported & affected by numerous known security vulnerabilities.

Please first update to Firefox 18.0.2. Firefox 12 has known issues and security holes and it can't be guaranteed to work with Flash anymore.

After doing that, restart your PC, and try downloading Flash using http://ninite.com/flash/ninite.exe. Adobe's installer is crap, using a standalone like ninite can often resolve install issues.

I'll try the standalone installer.... but I refuse to upgrade to any newer FF versions. The FF12 is the longtem stable version for enterprises if I'm not mistaken and there are still patches for it.

With every new version I need to find compatible plugins :-( It happened so often in the past that after the upgrade I had to wait weeks, sometimes months for having my favorite plugins working again. e.g. the Adblock pro, or the Orbit downloader plugin

You are mistaken, Firefox 17.0.2 is the current version for enterprises. 12 never was built for the enterprise and has not received a patch since almost a year ago. Also the enterprise firefox isnt made for end users, it is designed for enterprises with a dedicated IT staff. Regardless, 12 is out of date and insecure.

Plus, the situation with addons is better now. if an addon works in 12 it will work in 18

it seems this issue is some strange stuff from Adobe flas for firefox. I just went to youtube with an old laptop having Firefox 3.5 and Flash 10.3 and it plays clips there well. So the message "your flash plugin is outdated" was completely wrong. Reinstalling FF12 helped and I didn't need to put the flash thing into the browser again.

And I wanna stay on a version that doesn't get stuck for a minutes every second day while installing updates, then another minute "checking plugin compatibility".

hello, outdated plugins and outdated browser versions are the #1 infection vector on the web nowadays and this is widely exploited. so (mildly said) you won't do yourself any favour and more drastically said your putting the integrity of your system & all your personal data on it on the line.

firefox 12 has dozens of published security vulnerabilities that got fixed in later versions: https://www.mozilla.org/security/known-vulnerabilities/firefox.html

& adobe also just had to release an emergency update for its flash plugin to mitigate new exploits.

therefore i'd suggest again that you update firefox to the latest version and do the same with your plugins!

It was 10.0.*esr (10.0.12esr) that was the extended support version (not 12.0.*) and is now replaced by 17.0.2esr pretty much.