Confirmed Joe.  Just had an identical occurrence here. Win 7 Pro 64bit with 20GB RAM - Had to restart to track down what was causing it. I've exited Malwarebytes for now.

Thanks for confirming, Andrew. Also being reported at the MBAM user forum:
https://forums.malwarebytes.com/topic/219952-mbamservice-crushing-my-system-memory/
Regards, Joe

Incidentally, you'll need to disable it in services.msc or it will just keep restarting itself.

I'm tipping this will put a damper on their silly claims that Malwarebytes can make antivirus' obsolete lol  :)

> you'll need to disable it in services.msc or it will just keep restarting itself

Good tip, but I went one better...uninstalled it! :)

For those interested, it has been fixed with update package version 1.0.3803. The issue is discussed thoroughly in this thread at the MBAM forums:
https://forums.malwarebytes.com/topic/220112-important-web-blocking-ram-usage
Regards, Joe

Thanks for your update Joe.  I just re-enabled the Malwarebytes service and started it. Did an update and can confirm the issue has indeed been resolved. It's why I don't go to all the trouble of uninstalling.

Just about any software vendor will royally screw up like this at least once, so instead of uninstalling, I just disable and get on with my day. It also perfectly illustrates why I never rely on a single security package to keep me safe :)

You're welcome, Andrew, I'm glad it's resolved for you, too.

I also don't rely on a single security package, although you have to be very careful when running more than one...in some cases, they can conflict with each other and cause a lot of grief. That's why you hear the popular caveat of not running more than one anti-virus product on the same machine. Cheers, Joe