JLMoran

Thanks for the explanation, @treed. In my own browser / the settings for my family's user accounts, really all we have installed for extensions is 1Password and (in my case) Ghostery. So that's definitely not an issue. But I can see where the matter of downloading files to a suspicious location could cause issues on a site like Yahoo Mail; that inbox page has no less than 5 panels showing constantly rotating ads, so there is definitely a constant stream of "stuff" showing up that probably requires scanning.

Just took another look at the process and total CPU usage. Here is the latest: I checked my other high-CPU processes, and saw that my wife's user account had Safari open and also using a high level of CPU (about 50%). Killed that process, and now RTProtectionDaemon is only using 2-4% CPU, with frequent spikes in the low-40s: Not sure why RTProtectionDaemon is spiking like that, but at least I found a resolution to the issue and can confirm that it's not (at least not directly) an issue with the Malwarebytes app. Not sure what might my wife might have had open on her account (most likely Yahoo Mail, which has loads of ads constantly circulating), but I'm assuming there was something continuously cycling there that kept the RTProtectionDaemon process constantly scanning.

I am on v3.4.12 of Malwarebytes and I also have extremely high CPU usage from the RTProtectionDaemon process. Currently fluctuating between 57 and 78%. This is on a 2017 iMac 27" 5K Retina with 40GB of RAM and 4.2GHz quad-core i7. I can tell it's contributing to overall high system usage as all of the usual CPU hogs (Chrome, my daughter's copy of Fortnite, etc.) are all shut down but I can still hear the fans going on this iMac. This isn't good, especially since I saw threads from last year indicating problems with this process for both CPU and memory. Even though the RAM usage is fine now after the patches delivered last year (I see 287.5MB), the fact CPU is still so high indicates there are still some major problems with this process. So you've got at least one data point for the current release version. I've had a subscription since February of last year when I first installed it.