Finding the product key on a Mac with Catalina

I upgraded my MacBook to Catalina and Endnote X7 no longer works as it’s 32bits.

So I bought the upgrade to Endnote X9. But the installation requires the serial number of my earlier X7 version.

How do I find it since I can no longer open Endnote X7 on my Mac ?

Please contact Technical Support directly for assistance with locating your Product Key for X7.

1-800-336-4474 option 4 then 1