Was running the latest developer Sierra beta 8, so wasn't expecting anything to expire anytime soon. Fixed the problem by installing the most recent public beta.
[doublepost=1473553114][/doublepost]Hi, Try this to fix your problem. Go to Applications, Right click iTunes and choose "Show Package Contents" when the folder "Contents" appears just send it to the trash. Now you could go ahead and install the latest normal iTunes application since all that's left is an Icon from the expired iTunes. Hope this was helpful.
Ron