Start Firefox in Diagnose Firefox issues using Troubleshoot Mode to check if one of the extensions or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox (Tools) > Add-ons > Appearance/Themes).

• Don't make any changes on the Safe mode start window.
• https://support.mozilla.org/kb/Safe+Mode

I started Firefox in Safe Mode and I am in the Default Theme.I still get the same error message.

Can you post a link to as page where that happens or does it happen randomly and not always on the same site?

Does it help if you reload the page and bypass the cache?

Reload web page(s) and bypass the cache.

• Press and hold Shift and left-click the Reload button.
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Cmd + Shift + R" (MAC)

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Tools > Options > Advanced > Network > Offline Storage (Cache): "Clear Now"

"Remove Cookies" from sites causing problems:

• Tools > Options > Privacy > Cookies: "Show Cookies"

It happens randomly.I have removed cache and cookies.I did however unchecked the hardware accelerator ,and as of now have not had this error message pop up.

Is your Flash Player installed in default folder with installer?

Yes,the flash player is in the default folder with installer.

Which security software (firewall, anti-virus) do you have?

A random behavior can be an indication that other (security) software is interfering somehow.

A possible cause is security software (firewall) that blocks or restricts Firefox or the plugin-container process without informing you, possibly after detecting changes (update) to the Firefox program.

Remove all rules for Firefox and the plugin-container from the permissions list in the firewall and let your firewall ask again for permission to get full unrestricted access to internet for Firefox and the plugin-container process and the updater process.

See:

• https://support.mozilla.org/kb/Server+not+found
• https://support.mozilla.org/kb/Firewalls

I have McAfee Total Protection. Firefox and the plugin have full access within the firewall.I have unchecked the box associated with the hardware accelerator.

I believe to have found the solution to this problem.The issue is the screen saver.The problem started when I installed a screen saver.So I thought that maybe the screen saver was using flash.So I uninstalled the screen saver and then reinstalled the screen saver and no more "error message-can not find macromedia flash".