Does anyone know what would cause my Z axis motor to move in the

Does anyone know what would cause my Z axis motor to move in the direction of the table, whether I signal Z+ or Z-? I’m still learning how to configure my machine and properly flash the firmware updates. I made a breakthrough today when I realized that the size of my models were off because I entered mm/revolution incorrectly. That was tempered by my Z axis motor going haywire.

I also heard somewhere (Synthetos, I think) that a problem could be related to the fact I am using a Mac.