Here are the things we recommend that you try:
1) Load the original Mach4Mill profile and make sure that the PMDX
SmartBOB plugin is NOT in the plugins directory. See if this will
load and start reliably.
2) Make sure you have a machine that meets the minimum requirements
as listed near the bottom of the page here:
http://www.pmdx.com/Mach4Hobby We have seen significant problems trying to run without hyperthreading
support on signal core processors.
3) If the above do not help, please send us your configuration information.
As of build 2580 Mach4 now has a function to capture the
machine configuration and profile into a zip file. This is
useful when there are doubts about how the machine is
configured.
This function is under the Help > Support dialog. If you
use it, be sure to edit the email address to send it to
PMDX instead of MachSupport.