It is not advisable to have it turned on all the time for security issues. As well being constantly running in the Firefox Sandbox could slow your system and Firefox down.

When that popup in this case by image after you Click yes on that there should be a Firefox Information Box pop out from the Show Site Information beside the Padlock/Far left on the Address Bar. This should have options on it to Allow and to Remember. If Remember is clicked then from now on it would not ask you any more for this site.

If still wanting to risk your system go to the 3 Bar Menu then Addons and Click Plugins. Flash should be the last one and the far right of that s the settings for Flash. Default is Always Ask. Make your Choice there.

Please let us know if this solved your issue or if need further assistance.

If you click the plugin notification icon in the address bar and instruct Firefox to make an exception for the current site AND remember it (see example screenshot attached), Firefox should retain that instruction indefinitely. If your Firefox loses that when you exit and start Firefox again, check to make sure you are not clearing Site Preferences at shutdown.

You can check that here:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the left column, click Privacy & Security. Then on the right side, if you don't have "Firefox will: Use custom settings for history" select that option temporarily to show the detailed settings.

If you have a checkmark for "Clear history when Firefox closes", click the "Settings" button to the right of that and make sure there is NOT a checkmark for "Site Preferences" since that will clear your individual site permissions/exceptions.