i have the same problem… running ir and editing material at the same time is really pain… it only happens on my WS with 2x Xeon’s 2670 v1, made some tests on same scene on i7 4790K… and it’s working fine
3ds 2016 sp4, corona 1.6 db 22.11.2016, windows 7,
As i mentioned i have this big problem and my pc is one Intel Core i7 Extreme 980X @ 3.33GHz
3DMAX 2017 last update, Win 7 Proffessional
Corona 1.5 hotfix 2
So yesterday i updated all windows updates for my windows 7. For some reason it said it was updated even though it wasn’t. Anyways my corona is not freezing anymore (not yet at least). I will keep you guys posted if the problem returns but so far so good.
Solutions so far:
Anyway we would like to catch the problem live, so apply the solutions only if you really need them, and otherwise please report to us and let us take a look.
reboot system, start 3ds, open scene…
Mav3rick - sorry, this is just because people are using different names on the forum and over email - have you already contacted us over the support portal? If not, please do it here: https://coronarenderer.freshdesk.com/support/tickets/new
By the way - one more funny case - the issue disappeared for one user right before we connected to him through TeamViewer. It was consistently happening for at least 14 days prior that. 
Please, please, please find a fix for this bug. ATM Corona is practically useless on my work-machine (Dual Xeon E5v3). The problem seems to get worse - now it’s also showing up on max2016 (aswell as 2014), and the “short-term fixes” that worked before doesn’t work anymore (reinstall Corona and reboot the PC).
Only solution for now are: change PC (to a non-dual-Xeon) or change renderer.
Please, please, please make the fixing of this this top-priority…
Just please, everyone with this problem contact us by using this form:
https://coronarenderer.freshdesk.com/support/tickets/new
check in windows task manger - Services for Windows Update (wuauserv), if is running, stop it! then observe and report back
seems to be happening with every Corona version (including C4D & Blender)
Any news on this. I just started seeing this in Corona 1.5 hotfix2 with Max 2017.
It is not just the material editor, it is the whole UI from spinners, scrollbars to just moving in the viewport. Every 1 sec, it pauses/freezes. We are currently about to port our scenes over to Vray because it is not possible to work. We will currently stop our monthly rental and will be first in line to use Corona when this is fixed.
Is the a fix yet? Nothing here has helped.
Processor: Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz (2 Processors)
Windows 10 all updates.
Any updates on this? I am getting no support from Devs on this.
Hmm… I installed latest daily (Marts 1) on work Friday, and it seemed to work much better. But I haven’t had a chance to check it out in dept yet.
So try latest daily, and see if it helps
Me too, everything is fine with latest build on this issue. No slow downs at all.
So far it seems like the latest daily (Marts 1) has solved this problem!
Thank you
Hi,
I have this problem since a time while using interactive render. I try to diseable the material editor in the interactive section under System settings and its better, but… Cant see my material in the slot editor, not very accurate. Iam using a 72 cores Pc so iam not missing cores to render it…
Thx
Solved! hotfix2…
Hi fraymond3d. On my dual Xeon it’s solved in the daily builds. Try the RC1 from today, and see if it works for you.
Oh yes! thanks!
Works so fast with this daily build… cant stop wotk now 
Having this problem with 1.6 RC3
EDIT - Clearing ME with maxscript solved the problem. Possibly due to there being a vray material in the editor without having vray installed and max throwing a missing dll error every time the ME loads
Hello,
I am in trial licence yet, I am doing my first project in corona. I face same problem, Slate material editor is so unresponsive sometimes that I have to force closing. Also(out of this theme but) interactive mode seems to be very unstable, sometimes freezes and when I monitor task manager, CPU usage keeps going from %50 to %100 in periods, but it doesnt unfreeze for very long time.