Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Without knowing the steps you took in upgrading to Sierra, perhaps the best thing to do is to completely remove and then reinstall Office. Be sure to allow AutoUpdate to bring Office completely up to date.
Uninstall Office 2016 for Mac - Office Support
The current install download is
https://go.microsoft.com/fwlink/?linkid=525133
There is a known crash in Sierra that Microsoft is waiting for Apple to fix. If you are still getting a crash after remove and reinstall, you may have simply wait for Apple's update or revert to a previous edition of Mac OS and Office.
You might be able to fix the crash simply by updating Mac OS and Office. You didn't say which update levels you have with either Mac OS or Office. Here's how to ensure you're up to date:
Make sure your Mac has a working internet connection before checking for updates. Install Mac OS X updates followed by Office updates.
Mac OS X updates:
To get Mac OS updates, go to the App store on your dock, and then click the Updates button to reveal available updates.
Office Updates
To get the update:
- Open any Office application:
- Make sure your Mac has a working internet connection
- Go to the Help menu and choose Check for Updates
- Let AutoUpdate check for and install updates
- Restart your Mac