I'm trying to download and install Adobe Flash NPAPI plugin for Firefox. I have Windows 10, Firefox 62.0.3. I've tried everything I can think of, but it doesn't work. It will download and install, but when I go to a site that uses it, it doesn't work. I've disabled my Norton, Malwarebytes, closed Firefox and any program that uses flash during installation, installed as Admin, uninstalled and reinstalled, made sure Firefox wasn't using hardware acceleration, set flash to "ask to activate", wasn't in protected mode, uninstalled Ad block, disabled other add-ons and extensions, etc. I've been trying to get this installed and working for 3 weeks. One time after I installed it I checked on the Adobe site to see if it was installed and it worked. I went to a couple sites and it worked. But for some reason the next time I went to the same site that it worked on an hour before, it no longer worked. I rechecked it on the Adobe site and it was no longer working. So once again I uninstalled and reinstalled, many times, but it never works. I really don't want to have to switch to Edge every time I visit one of the sites that uses flash, but I'm tired of all the installing, uninstalling, and reinstalling. I've researched online and tried every suggestion I could find but nothing works. Can anyone help solve this problem?
Unless an installation error displays, Flash is installed successfully. You didn't mention any installation errors, so I'm going to assume it installed fine.
Firefox, as with other major browser vendors, disable/block Flash by default, forcing user's to enable it, usually for every single site and sub-domain (e.g. www.adobe.com and helpx.adobe.com would be considered different sites).
The browser is what controls the loading of the plugin, not the plugin. On the same token, the content developer also has to ensure their Flash detection conforms to the constant changes in how browsers handle Flash, which is quite often. Most browser vendors have published Flash Roadmaps for how they're going to handle Flash until Flash's end-of-life at the end of 2020, and content developers (big & small) need to be cognizant of this and update their content accordingly, or migrate off Flash.
If you haven't done so yet, please see Why do I have to click to activate plugins? | Firefox Help. Firefox also blocks some domains by default, meaning, they will never enable Flash on those sites. For more information, see The Flash plugin is blocked on some sites by default | Firefox Help and Blocking By Domain - Plugins | MDN
If you provide the exact link to problematic sites, I'm happy to take a look, however, from your post it sounds like you need to contact the content developer and/or Firefox for assistance. Flash Player has no bearing on the browser vendor's rules for loading Flash, blacklisting sites, etc.
I'm not sure what the problem is, or what's causing it but I've given up on having flash in Firefox. I updated Firefox to the latest Firefox version and tried again to install flash. After a couple unsuccessful attempts it finally worked. For a short while. Immediately after installing I went to the Adobe flash checker and it worked fine. The tree grew and the clouds moved. So I checked a couple websites. It worked. But once again after a very short while, when I returned to one of the sites, it froze. The whole page was locked up. This had happened a few times before when I installed flash. I had to go to task manager and under Firefox it showed the flash plugin, but it wasn't using any resources, nothing. When I stopped the plugin it disappeared and immediately appeared again only this time it was working and when I closed task manager the site was working and so was flash. But it never lasted long. The next time I went to that site or any site using flash, including the Adobe flash check site, flash no longer worked. So after weeks of installing and uninstalling, and doing everything I could think of, including all the suggestions I found, I uninstalled it and have given up. I open Edge or IE when I go to one of the sites that uses flash. It works in those browsers without a problem. I prefer and use Firefox and would rather not have to open a different browser when I go to those sites but it's impossible to get flash to work correctly in Firefox. I never had an issue with flash until either the last Windows updates or Firefox Quantum came out. I'm not sure which one began my flash problems but I'm convinced it was one or the other.
it sounds more a Firefox issue than Flash. Did you try to update your video card drivers? I suggest you open an issue at Firefox with the link of this discussion.
I was trying to install adobe flash for firefox, I used windows 9, firefox68.0.2, but I could not manage my website because of my server issues.I've disabled my closed Firefox and any program that uses flash during installation, installed as Admin, uninstalled and reinstalled, made sure Firefox wasn't using hardware acceleration, set flash to "ask to activate", wasn't in protected mode, uninstalled Ad-block, disabled other add-ons and extensions, etc. Then I got a solution from online how to recovery my server and also adobe flash. If you want to get more details by following Mozilla firefox can't connect server.