For Mac computers, we recommend using mBlock 5. It is a free download and can be found here: https://www.mblock.cc/en-us/download
If, for whatever reason, you must use mBlock 3, you will need to update the mBot drivers before you can connect your mBot to a Mac running macOS® 10.12 (Sierra) or newer, . Click on the link below and run the installer to update those drivers.