We have been testing Windows 10 and Office 2016 since their release. This is one of the system error messages we've come across with Office Professional Plus 2016: "Sorry, we ran into a problem while trying to install the product key. If this keeps happening, you should try repairing your office product. (System error: 0x80041015)"
After uninstalling and re-installing, troubleshooting, and searching online for a solution, we spoke directly with Microsoft and received the following solution.