It's a font issue! At least it is on my computer. I installed the 15.16 update and got the usual grant access problem.
I use Extensis Font Suitcase to manage fonts & I keep a lot of fonts loaded - I've been using it for years that way without an issue, but I've had this nagging feeling that fonts were behind the other Word issue I was having with blank menus. As an experiment,
I used Suitcase to clean the font cache, which restarted the computer, but Word loaded before all the fonts loaded. And Word finally worked properly. Then I restarted the usual way, with fonts loading first, and the Word problems came back.
Now I've deactivated every font except the essential ones in the System/Fonts folder and Word again works properly. Plus it's resolved the problem I've had for a long time with with Preview unable to grant "permission" to view more than one document at a
time.
So is it a particular font or is it the number of fonts causing the issues? I'm interested in knowing if this information helps anyone else.