Your DMXIS license is linked to your DMXIS hardware, NOT the computer running the software. Therefore, you can install the DMXIS software onto as many Windows & Mac computers as you like. The DMXIS hardware must be connected before you can actually transmit any DMX data.
When you unlock your DMXIS software for the first time (at enttec.com/unlock-dmxis) you will receive a 6 character unlock code (e.g. “axpsfz”). For full peace of mind, unlock the software once on a Mac and a PC (as the codes are slightly different) and stick the two unlock codes onto the DMXIS interface. Then, you know you will be able to install and use DMXIS on ANY computer, even if you have no internet connection.