Malwarebytes and Windows Defender on Windows 10

If your system has internet access of some sort, it's not a good idea to run without some form of live protection.

So to the main point of your question, generally two security programs will not play well together. So you are lucky that it has worked for you so far. I would not recommend it going forward because the two could conflict with other and cause something to be missed and you would never know.

Having said that, Windows Defender works very well on its own in a standalone situation. Paid for product are usually better than free products, of course.

I have had windows 10 on my system with Windows Defender, without any issues, for a number of years. I do a manual scan with Malware Bytes from time when something seems amiss. Windows Defender does to a good job in protecting me as I never have any viruses or malware on my main computer.

i have been giving all my customers windows 10 without any other AV than WD - no problems reported yet
So my advice is : for standalone PC's use ONLY WD - nothing else

and remember - there's no AV that guarantees 100% protection

You should never install 2 anti-virus programs, as they can fight with one another, but installing a malware program along side an anti-virus is just fine and actually a smart thing to do.  Then ensuring they are run regularly becomes critical.  Personally, I'd install and run both and yes, I'd run MBAM manually (I find their real-time mode to be a computer killer absolutely remarkable at slowing down computers to a crawl - wasn't always the case)

As for protection, I have had less clients infected running WD than many others (AVG, AVAST to name but 2).  

That said, there are always new viruses, malware so even the best software can stop everything.  The best protection is the user being responsible, not navigating everywhere without knowledge, not downloading and installing all sorts of software, not opening unknown e-mail attachments, not authorizing website pop-ups, ...

>>   but installing a malware program along side an anti-virus is just fine and actually a smart thing to do  <<  i don't agree - as you can read above; it "may" have been so in the past - but no more needed now
>>  Then ensuring they are run regularly becomes critical.   <<  as i know my clients - that is NOT done; may be a couple do it out of hundred

but no more needed now

The more tools you have in your arsenal the better you are off.  No one tool does it all and there is no downside to having a dedicated malware tool such as MBAM.

Then ensuring they are run regularly becomes critical.   <<  as i know my clients - that is NOT done; may be a couple do it out of hundred

No argument on most people don't do it, but this doesn't mean it shouldn't be done.  In some instances it can be scheduled to be performed automatically.  And if your end-users can't do minimal scanning themselves, them real-time solution becomes required.

My own experience and working with several small offices included is Windows 10 with Defender has been sufficient. The exception has been for the bored employee that does everything on the internet but their job including hitting bogus sites for things like coupon clipping that elicit a  lot of spam with links that elicit more spam and load up the browsers toolbars with junk.  Things have been easily fixed using Microsoft anti malware removal tool.  

The best protection I found has been education. Teaching users things like "Quickbooks calling to sell support" and the fake domain renewal letter. Teaching users to make sure windows is up to date but not getting the latest update right away.

I do feel a good user like yourself is going to do well with windows defender. I have used just that myself for the past 4 years or so.

@Scott
All very valid points!

i believe there are 2 options : with or without AV
i have made my choice - but note that i said " for standalone PC's"
and if people want to install  an AV - that's up to them, and that will be respected by everyone

Any decent modern av has a builtin cache, ignore list, and a bunch of other strategies that prevent them from scanning one another in a loop. so, expect them to play well. Check with filemon or a similar tool if needed.

I concur that a careful user behind a basic nat router can stay safe for years. I ran a  win2k machines with a public ip for quite some time. Back then, i had to do some hackish hardening. More recent versions should not be run without at least a nat router.

That does not mean it is a good idea.

Having a browser running with low privileges in a separate session and a decent  mail filter is one of the keys to expect some safety.

whatever you setup, clicking all over the place without thinking, downloading random software from unsafe sites and other such behavior WILL DEFINITELY end up with an infection of some sort. even with the best av or avs in the world. Relying on avs only is over optimistic.

My thanks to everyone who participated...I'm very grateful for your feedback. Fair to say that there's no absolute answer here...some folks think that WD only is fine, others think WD with occasional, as-needed manual runs of MBAM is the way to go, while still others think that both can run with real-time protection enabled. As there is no obvious "correct" answer, I've selected what I think are the two best posts as the "solution", and marked many of the others as "helpful". Thanks again for your comments. Regards, Joe