While using the Mozilla Firefox web browser, depending on the current security settings, attempting to view a video item in Media Collections Online may result in a blank entry accompanied by an item's description:
It may also display either of the following messages:
These error messages indicate that Flash is either permanently disabled within your browser or requires permission in order to run. To check if Flash has been permanently disabled, view the settings for Add-ons within the menu at the top-right corner of the browser.
Select Plugins from the left-hand menu, and change the settings for Flash (which might be listed as Shockwave Flash) to "Ask to Activate." It is not recommended that Flash be set to "Always Activate," as Flash is no longer as secure as modern solutions and may open your computer up to security risks when visiting unfamiliar sites.
Reload the MCO page, and select the Flash icon next to the address bar. Select either Allow Now or Allow and Remember (which will add MCO as a trusted site within Firefox):
Flash should now be enabled within Firefox, and the item should load immediately.