Yeah, we don't want content to trick you into downgrading by providing you with an old version, so that they can use a known security issue from an old version against you.
In order to move backwards, you have to uninstall Flash Player, then you can install the older version.
That said, running an older version puts you at significant risk for malware infection, as it only takes the exploit kit guys 1-2 weeks to reverse-engineer and weaponize fixes in a new release these days. It would be better to run the current version and see if we can help you out with whatever it is that's not working in the latest Flash Player. Plus, we'd like to know what we broke. It's not always easy to anticipate the outcome across all of the possible Flash content in the world when we're dealing with some really fiddly security change in the guts of Flash, but when we break stuff, we try to clean it up quickly.
Thanks for the reply. I understand there are security risks involved with downgrading (I was attempting to get the most recent major version to preserve the security and only alter the features). I tried using the flash player uninstaller, but still could not install any version of flash player from the archives.
I am having trouble specifically with the Firefox addons Reddit Enhancement Suite (RES) and Better Twitch TV (BTTV). To access RES, there is usually a gear icon on the website reddit.com, however this is no longer visible. Similarly, there is a gear icon to access the Better Twitch TV options that is no longer visible on the website twitch.tv. The RES addon can be found through Firefox, but the BTTV addon is 3rd party software.
It doesn't make a lot of sense that a Flash Player upgrade would affect a third-party Firefox extension. There's no way for other plugins to hook into Flash unless you've disabled ProtectedMode (which is also a bad idea from a security perspective), and we don't hook into other plugins. I'm wondering if maybe some internal Firefox configuration files might have been corrupted.
Are you running the right installer when you download the Archives? There's an ActiveX installer for Internet Explorer, and an NPAPI plug-in installer for Firefox.
If you need to run an older version, you're way better off using the Extended Support Release. It's an old feature branch, but with all the security fixes between now and then. We updated it in parallel with our current release.
Just scroll down to the Extended Support Release section and choose the second row - EXE installer for plug-in based browsers:
Once you've run that installer, if you still don't see Flash Player, then my guess there's either a bad registry entry or Firefox config file in play.
It won't do a lot of good trying to fix it if the filesystem is in a wonky state, so it's worth ruling that out first:
Caveat: Sometimes corrupted software is an early indicator that your disk is going bad. It's wise to ensure that you have current working backups, especially if you have anything important on the machine. Checking the disk for problems is a relatively safe operation, but will also give the disk a workout. If it's on it's way out, you may not get a lot of additional warning.
Checking the disk for errors:
At that point, if you identified problems and fixed them, but things still don't work, it's time to uninstall both Flash Player and Firefox and reinstall from pristine sources.
If you're still stuck, let me know.