Hi,
don't know if this will help but probably won't hurt...
On the config tab there is a 'select native units' page. Make sure it is set to mm.
These are the units used to tune the motors.
You can still machine in inches if you wish but don't use this setting, use either
G20 or G21 codes.
Another tip is on the 'general configuration' page of the config tab is about middle of the screen
an initialisation string. It is a set of Gcodes that run each time Mach fires up. If you edit the
initialisation string to include G21 then you will always start in mm.
Incedently my machine would always start up with a federate of only 6mm/min, safe but really
slow until you MDI a more reasonable speed to set things up. I set up a F300 in the initialisation
string which gives me a more useful default start up federate.
Craig