I have been using Mach3 for more than a year now and have not noticed this problem before. I have no problem homing my system after start up and can use the tool probe and the park position which are both set to Z-2.5. After doing a tool probe and it auto zeros if I go to park position, tool change position or at the end of a program run, the machine wants to go to Z-2.5 which is now below the table. Have I missed a setting or not understand how Mach3 works. I have watched all of Paul Campbells videos and thought I understood. Z+ is up and Z- is down right? If it helps, I am also using the 2010 screenset. Any help would be appreciated.