This is probably fixed in SVN trunk, but we need confirmation.
Can anyone verify this behavior? I ran this on a 4-core Windows 7 machine with the OpenMx Beta and R 3.1.0. omxDetectCores() gave me 1, instead of 4 or 4-1=3. The task manager showed all four cores active during optimization, but total CPU usage was around 25%=1/4. When I tried to modify the number of threads used by setting the option to use 3 threads, I did get a crash from R.
Mike Neale reported a protection stack overflow to the openmx dev list. Maybe that is why it is crashing on windows?
Please try with 3650.
With the 2.0 Beta (r3751) this works for me on Windows.