Please try the following: In the GUI, go to Edit / Preferences, then the Shortcuts tab. Is the “Disable global shortcuts when Command Window has focus” checked or unchecked? If you change the option, does the ability to use Ctrl-C / V change?
I could not copy-paste with CTRL+C and CTRL+V either w/ 7.1.0, and unchecking the mentioned box worked for me too.
I had not uninstalled 6.4.0. I was looking to it for reference to get 7.1.0 to behave similarly, but that box was checked and I could copy-paste with CTRL+C and CTRL+V.