After downloading Overdrive MEDIA PLAYER. I must download media player security upgrade as always.

I've never had trouble till I tried putting it on Windows 8 Pro. After a successful download. I must download the media player security upgrade.( It seems like whenever Microsoft comes out with another operating system I must download the same old upgrade.).

A popup box tells me" windows media player encountered a problem while playing The file". Then no upgrade.

I've looked for answers but cannot find the right one..

The issue you have metioned seems to be very confusing.

You had installed the media player security upgrade when you were using the Windows legacy operating system and now when you upgraded to Windows 8, the same media player security upgrade is not present on the computer and due to which you get the error "windows media player encountered a problem while playing The file" Is this what you are trying to explain?

If this is the issue, then try installing the media player security upgrade again. I think you can do it from this:

http://drmlicense.one.microsoft.com/indivsite/en/indivit.asp