"Malwarebytes" is a glorified, over-hyped adware scanner, and little else, based on "Adware Medic," a free program written around 2014 by Thomas Reed.
Note that the software's name ("Malwarebytes") used on MacUpdate, curiously, is not the one used on the company's website. That name is "Malwarebytes for Mac." Also, it is described here (under the name) accurately as an "Adware removal tool." That description is not on the website, and the company strongly suggests that the software does much more, e.g., "Removes malware, including Trojans."
According to the Release History on the Malwarebytes website, "Malwarebytes for Mac" was launched on July 31, 2017, starting, oddly enough, at version 3. This was done evidently for marketing purposes, to align it with products for their other platforms.
Malwarebytes was already offering a product called "Malwarebytes Anti-Malware for Mac" (call it MBAM), originally launched on July 15, 2015. MBAM was essentially a renamed version of Mr. Reed's "Adware Medic," issued when he went to work at Malwarebytes.
According to the company's website, the last update to MBAM, version 1.3.1, was issued on October 17, 2017. According to the company's website, MBAM was on sale until February 15, 2018. It's "End of Life" is scheduled for August 15, 2018. (Who knew?)
The nomenclature used by Malwarebytes is confusing enough on these overlapping products. But more confusing, and more likely deliberately deceiving, is the notion that they remove all "malware," a term the company never bothers to precisely define.
What MBAM (and before it, "Adware Medic") does (or did) was to remove "active" infections of a small subset of what most Mac security people refer to as "Mac malware." I have no reason to believe that "Malwarebytes for Mac" expands on that subset. Nor do I believe that Malwarebytes even publishes what is included in that subset, though you do see the names whizzing by as MBAM runs. They certainly do not inform customers that it is only a fraction of all Mac malware. On the contrary, they strongly suggest that "Malwarebytes For Mac" all you need to protect your Mac.
You can download a "sample" of 108 instances of actual Mac malware from Patrick Wardle's objective-see.com. Unpack them and you have 108 pieces of live "malware" (by any definition) which are just waiting for you to click on them so they can infect your Mac.
I ran ClamXAV against this sample and it found just about all of them.
How many did MBAM v 1.3.1 find?
When "Malwarebytes for Mac" (which, again, is known, incorrectly, on MU as simply "Malwarebytes") first came out I loaded it up and ran it. But after trying to use it, and after reading the reviews here, I unloaded it and went back to MBAM. I do not know if "Malwarebytes For Mac" would find any of those 108 instances of malware, but I seriously doubt that it would. Someone else can test that.
However, I did upload a half-dozen or so of the malware samples to virustotal.com. On Virustotal, "Malwarebytes" (presumably the latest version of "Malwarebytes for Mac," though the site didn't specify) found the same number as MBAM did:
I urge you to read this review of "Malwarebytes for Mac Premium" from August, 2017, a month after it launched:
This article confirms that "Malwarebytes for Mac" only scans for "active" malware. It refers to an independent testing outfit that does not certify "Malwarebytes":
I conclude that "Malwarebytes for Mac" is still little more than a scanner for active adware infections, and perhaps a few other bits of malware, already running on your Mac, with a paid option to do real-time checks for a small (and again undefined) subset of Mac malware. It might do a decent job with this, but the point is that, in boasting to Mac users that it "crushes the growing threat of Mac malware," it pretends to be a comprehensive solution to protecting a Mac.
This is deceptive nonsense.
If you believe Malwarebytes' marketing, that all you need to protect your Mac from "malware" is their product, you have been badly, and deliberately misled. As much as I have respected Thomas Reed up to this point, this is a huge hit to his reputation. Frankly, I hope he goes back out on his own, because his contributions, buried deep in the company's website, are being wasted there.
As to Mac users, we're stuck trying to protect ourselves with a myriad of products whose functions overlap, price points differ, and many of them saying they're the best and/or all you need. It's a mess with no end in sight.