Try running Font Book. Can it see the font? Use the search box in the top right of the font book window to search for “Copperplate”.
The middle column of the window should show the Copperplate font family with Light, Regular and Bold listed underneath it. If you don’t see that there is something wrong with the way the font is installed.
Is the word “off” listed to the right of the font name and the weights? If so, the font was disabled somehow. Single-click on Copperplate to select it then click the empty square above it (to the right of the “+” sign) to activate it.
On my system the show font info window shows the font location as /Library/Fonts/Copperplate.ttc
Mark Landman
PM Productions
Champaign, IL