As a workaround for known segmentation fault problems with the compiler (avr-gcc 5.4.0-atmel3.6.1) associated with the 1.6.22/23 avr board manager versions, I reverted to board version 1.6.21 using the board manager in Visual Micro.  Subsequently I (well, not me, but a knowledgeable person on the Arduino forum) was able to determine conclusively from a verbose compiler output that the Arduino IDE was indeed using V1.6.21 and the v4.9.2-atmel3.5.4-arduino2 compiler.

However, that same person was also able to show conclusively that when the same project was compiled in the VS/VM environment, VM still used the avr-gcc 5.4.0-atmel3.6.1 compiler associated with 1.6.22/23.  I have since checked and double-checked that the VM board manager dialog shows that board manager V1.6.21 is installed, but clearly VM isn't honoring my board manager version reversion from 1.6.23 to 1.6.21.

For all the gory details, see http://forum.arduino.cc/index.php?topic=577826.new#new

Any thoughts?

Frank