Using mame.ini

video d3d
numscreens 2

The following above crashes from MAME 0.162 to 0.192
Works with all older versions up to MAME 0.161

What hardware are you using for dual displays ? Are you using 2 video cards ?
I have both monitors using two different ports from same Video Card. Never had issues for years but considering you dont have issues with dual displays I suspect some incompatibility was created after v0.162.
Tomorrow I can try install a 2nd video card and plug each monitor on different video cards.