Trying to build an ESP32 project. I get an error including <Wire.h> . See the barebones sketch below. I recreated the error on a completely new virtual Windows 10 machine with Arduino IDE 1.8.8, VS2017 Pro and Virtual Micro 1811.24.0. I installed ESP32 board support via Arduino IDE. I must be doing something fundamentally wrong - I just can't see it.

The barebones project compiles under the Arduino IDE

I turned on various debug options and noted "Core Include Paths" did not include the actual path to the ESP32 location of Wire.h 

The Wire library encountered an unknown path resolve error.c*: 30:17: fatal error: twi.h: No such file or directory
   compilation terminated

#include <Wire.h>
void setup(){}
void loop(){}

"Physician, Heal Thyself"
Thank you for your quick supply.
It must have been the issue you noted -  the extra copy of Wire library not under a board specific location.

Simple sketch that includes <Wire.h> now compile under VS2017/Visual Micro.

I was convinced that it was something that I was doing wrong. I spun up another virtual machine with Arduino, VS2017 and Visual Micro. This test machine worked - which proved that it was something I did wrong.  I then went back to the failed laptop and uninstalled Arduino and Visual Micro. I deleted folders: %userprofile%/appdata/local/Arduino15, c:\program files (x86)\Arduino and %userprofile%\documents\Arduino. (I saved sketches of interest). I reinstalled the tools and verified correct operation of VS2017 with a simple sketch that included  <Wire.h>

This thread can be closed.
Again, thank you for your reply and assistance.