Updating visual studio 2016
Again, see the Platform Targeting and Compatibility article for details on project support in Visual Studio 2017.
The following list describes support in Visual Studio 2017 for projects that were created in earlier versions.
I removed all of the Word add-ons and the load time is pretty much the same with or without the add-ons under 1709 (painful).
I can go through all of the steps I went thru to isolate the problem (I have over an inch of notes) even reinstalling Windows 10 Pro and Office 2016.
When I reimage the computer to Build 1703 all the Office application load problems revert to what I use to know as nominal start up times.
Example: Word 2016 takes over a minute to load under Build 1709, 15 seconds under Build 1703 and a safe mode start to Word loads in 3 seconds.
If you don't have the workload installed, Visual Studio reports an unknown or incompatible project type.
In that case, check your installation options and try again.
(See the Release Notes for which features are specific to which versions.) Support for some project types also changes over time.
Note also that some project types are no longer supported in Visual Studio 2017 at all and therefore cannot be migrated.