Using an Adminstrative account, try running:
sfc /scannow
from the Command Prompt.
If that doesn't fix the problem, try removing Office completely (see Options 2 & 3 at
https://support.office.com/en-us/art...c-2fdf5dbf61d8) then reinstalling. An ordinary uninstall leaves certain files & settings behind that a reinstall without complete removal will retain - and it's possible one of those is the culprit.
FWIW, there's an ongoing discussion at:
https://answers.microsoft.com/en-us/...c-8a6850b54101
Ignoring all the cut&paste/nonsense/off-topic posts in that thread, it seems there's an unresolved issue that affects multiple PCs on Office 2016.