Malwarebytes is not yet compatible with High Sierra
Later this fall, Apple will be releasing an update to their Mac OS. This version will be called High Sierra and it's version number is 10.13.
Malwarebytes for Mac version 3.0 is currently not compatible with High Sierra. We will be releasing an update that will be compatible with High Sierra prior to the public release of High Sierra. In the meantime, be aware that Malwarebytes for Mac will not function properly on High Sierra.
Malwarebytes Anti-Malware for Mac version 1.2.6 has also been broken by the latest High Sierra beta (beta 4, build 17A315i). As a legacy product, we will not be providing a fix for the incompatibility. Future versions of Malwarebytes for Mac, starting with version 3.1, will support High Sierra.
If you are using a beta of High Sierra, you will be unable to use our Mac products. High Sierra beta builds are still highly dynamic and are not meant for use in production environments. We will have a version of our software that is compatible by the time High Sierra officially releases.