Hello, are you using CentOS for personal use? This is not really recommended as it is built for server stability with older but stable versions of programs on purpose. Ubuntu has no problem with this.

Mkll said

Hello, are you using CentOS for personal use? This is not really recommended as it is built for server stability with older but stable versions of programs on purpose. Ubuntu has no problem with this.

Yes, I am using for personal use. I have problem with some of my software cannot run on newest Centos 7.4 so I don't update centos to latest.

Have you tried reinstalling Flash from your package manager?

It appears the current Flash Player 28.0 is detected in your More systems details on right of post.

If Firefox was still running when you install a version of Flash Player then either restart Firefox or type about:plugins in the Location (address) bar to scan for NPAPI Plugins it can use, in this case only Flash Player.

Note some sites may actually be using the HTML5 player in Firefox so make sure you have FFmpeg installed to fully use it.

Do you see the Shockwave Flash plugin on the about:plugins page and under Plugins on the about:addons page?

Firefox 52 and later releases only support the Shockwave Flash plugin and disable all other plugins. If you need to use other plugins then you can use the Firefox 52 ESR release. Otherwise you can stay with the current Firefox release version.

Why-do-Java-Silverlight-Adobe-Acrobat-and-other-plugins-no longer work.

• https://support.mozilla.org/en-US/kb/npapi-plugins

cor-el said

Do you see the Shockwave Flash plugin on the about:plugins page and under Plugins on the about:addons page?

---

Firefox 52 and later releases only support the Shockwave Flash plugin and disable all other plugins. If you need to use other plugins then you can use the Firefox 52 ESR release. Otherwise you can stay with the current Firefox release version.

Why-do-Java-Silverlight-Adobe-Acrobat-and-other-plugins-no longer work.

• https://support.mozilla.org/en-US/kb/npapi-plugins

Hi, I modified /usr/bin/firefox to change path to local firefox 57 where I installed manually and now, it can load Shockwave plugin in about:plugins. But it still cannot play flash . Does anyone here have same problem with me - Plugin was loaded but cannot play ?

What is the setting for Flash in "Add-ons -> Plugins"?

If "Ask to Activate" isn't working then try "Always Activate".

You can find a Lego block icon at the left end of the location bar indicating that the web page uses a plugin (Flash) that Firefox might block. You can click this Lego block icon to allow or block this plugin.

• https://support.mozilla.org/en-US/kb/why-do-i-have-click-activate-plugins

diodeszener said

I modified /usr/bin/firefox to change path to local firefox 57 where I installed manually and now, it can load Shockwave plugin in about:plugins. But it still cannot play flash . Does anyone here have same problem with me - Plugin was loaded but cannot play ?

As I mentioned earlier. James said

Note some sites may actually be using the HTML5 player in Firefox so make sure you have FFmpeg installed to fully use it.

James said

diodeszener said

I modified /usr/bin/firefox to change path to local firefox 57 where I installed manually and now, it can load Shockwave plugin in about:plugins. But it still cannot play flash . Does anyone here have same problem with me - Plugin was loaded but cannot play ?

As I mentioned earlier. James said

Note some sites may actually be using the HTML5 player in Firefox so make sure you have FFmpeg installed to fully use it.

Thank you. From your reply, I see that firefox can play flash video now, but not support H264 and H265. I will try to install package as your mention. Thank you again.

Forgot to mention, a page you can use to see if you fully support HTML5 player in Firefox/SeaMonkey as all checks should be blue. https://www.youtube.com/html5/