Windows Defender or 3rd party?

THIS IS IN ALL CAPS - DELIBERATELY - IT'S ANECDOTAL AND I COULD BE COMPLETELY WRONG. IT'S JUST WHAT APPEARED TO HAPPEN WHEN I WAS TRYING THINGS YESTERDAY!

Had a chance to shut everything off yesterday and try Lightroom... Couple hours of mild beating on it (which is more than enough to lock up normally), and near as I could tell, no problems...........

Turned everything back on - CONTINUED to run fine...

Rebooted. Back to normal - starts slowing down, gets worse, eventually have to kill LR and restart it......
WHAT would be different between shutting all the Windows Defender stuff (that I can get at) off, turning it back on, and rebooting?

Do I try sticking Avast or Bit Defender or SOMETHING on the box, killing (somehow) Windows Defender, and see if the issues stays gone?

Yesterday, I disconnected from the Internet access point, shut down WD real-time protection, shut off all the firewall stuff I could, started Lightroom and did "normal" stuff...

In a smaller than normal catalog, running on an SSD, with the IMAGES on a different SSD, this SHOULD have been a combination that is as fast as I'm ever going to get. And it appeared to be... Couple hours, normal processing, LR gobbled up about 15GB of memory (it ALWAYS gobbles up 13-15-18GB of memory so that doesn't change with the antivirus), but as near as I can tell it DIDN'T slow down.

Turned back ON Windows Defender and all the Firewall stuff, and reconnected.

Tested again, same images, new images, normal stuff... DIDN'T SLOW DOWN as near as I could tell.

REBOOTED............................................................................................ ....

Back to normal. 30-40 minutes and its draggy. Much longer than that and I have to shut it off and restart 'cause it gets unusably slow. If I DON'T shut it down, amazing, chaotic, extremely unpleasant things happen that frequently make it impossible to even kill Lightroom from the Task Manager and I end up shutting down or crashing the system... Actually, at that point I can't even shut down 'cause I just have a black screen - not the BSOD, just black and it's not coming back.

TODAY, I installed Avast Antivirus Free to see if having it replace Windows Defender would fix the problem. Rebooted, started Lightroom and it was the same as yesterday - 30-40 minutes and it's dragging.

SO, presuming I'm correct and NOT just engaging in wishfull thinking, what's the reboot do that would make such a drastic change? And if a different Antivirus (presuming it's not the firewall stuff or some other appalling thing that Windows Defender is doing) doesn't help, why dump Windows Defender?

And I got pointed at the article over at Microsoft from October, 2016 about "Windows Defender Real Time Protection Service slowing down file access", but I can't imagine that Microsoft hasn't fixed that in TWO YEARS...

So, shut off WD, disconnected, things appeared to work ok. Reconnected, still ok. Rebooted back to dog feces. Change antivirus, still the same.

Anybody got any idea what to try next?

f14tomcat said:

I have had Malwarebytes and Defender running concurrently for a very long time. MBAM did not disable Defender, and Defender did not disable MBAM. Both real-time. I'm certain others have also. Not just MBAM.

Same here, both MAMBAM and Defender running in real time. Never had any issues.

Hey GracieAllen,
WAG, but I wonder if Fast Startup could be the issue .... If you have Fast Startup on, have you tried turning it off?

Turn On or Off Fast Startup in Windows 10 | Windows 10 Tutorials

I"m sure I have it on, and I've never thought about turning it off. I'll have to try it next time I reboot.

As far MBAM and Defender, I believe that's what I've had on by default, and I was told to shut ALL the Windows Defender stuff off. Nobody said anything about Malware Bytes.

But, I can shut that off too, though I'm starting to have serious doubts that ANY of this antivirus, firewall, malware stuff is going to have such a significant impact but not for 30-40 minutes.

GracieAllen said:

And I got pointed at the article over at Microsoft from October, 2016 about "Windows Defender Real Time Protection Service slowing down file access", but I can't imagine that Microsoft hasn't fixed that in TWO YEARS...

I'm here to tell you it isn't fixed.

I've developed major slow down issues on pretty much any operation in the last 2 or 3 weeks. Before that, all was well.

Happens dozens of times per day, whether using a browser or not. System stalls and is not responsive to the mouse.

It turns out that Antimalware Service Executable is using 30% of CPU, which you'd think would be acceptable, but you can't even scroll a document until CPU usage settles back down to 0 or 1 percent. Which might take 20 seconds, while you twiddle your thumbs.

You can turn off real time protection to resolve it, but it won't stay turned off unless you use the registry fix found in a tutorial on this site. Which is what I did and no more issues for the time being. I'm relying on Malwarebytes for real-time protection.

This is on Win 10 Home version 1803. I have no idea if Microsoft is working on the problem.