Service host using lots of CPU

I have Glasswire Pro on my Windows desktop. Every week or so, a process called “Service Host: Local Service (No Network) (3)” will begin using tons of CPU time. Windows Defender Firewall is one of its three sub-processes, which is why I suspected GlassWire. Sure enough, when I kill the GlassWire Control Service, the process stops using CPU. I have also been able to stop the process by resetting Windows Firewall to default settings, but I do not want to do that every week.

I have also tried reinstalling GlassWire. Does anyone have any suggestions?

I am also having this issue since Glasswire 2, I do have a year of history with the app as a fyi.
It does eventually stop after a while.

Do either of you use Bittorrent? If so, try using it while in “Incognito” to decrease CPU usage. GlassWire has to work hard to keep up with so many simultaneous hosts.

No not on this machine, this happens when windows boots and after around 10 minutes the cpu load drops to normal levels, I noticed it happening on my machine and I thought it may have occured when I went to v2 of Glasswire but was not sure and didnt have time to test fully. Reseting Windows Firewall config or just waiting normally resolves it but it does seem to keep happening.
In firewall of glasswire I do notice I have rather a huge list of inactive apps but I dont know if that would affect anything as I have been running Glasswire with over 1 year of history.

Running Windows 10 Pro x64 FCU.


When you experience the high activity does your graph show any unusual network activity with lots of hosts, or anything else unusual?

Nothing obvious sadly, it only happens on start up and regardless of leaving the pc idle or starting apps. Based on what I googled at the time there were theories of apps interacting with the firewall but I dont reboot often but I did suspect it was possibly glasswire 2.0.

Is there any high disk usage when this happens? Or is it just CPU? It seems that Windows 10 likes to run certain housekeeping tasks right after boot. I really notice this with a laptop running a standard HDD, but on my desktop with SSD, these tasks are barely noticed. And the laptop was doing this before I installed GlassWire.

Right it does seem to be Glasswire, if I kill the service the Base Filtering Engine cpu usage goes right down.
I noticed in Windows Firewall I have over 2000 rules created by Glasswire, I shut down Glasswire and removed both the incoming and outgoing and restarted Glasswire and it seems to be recreating them all which started using a lot more CPU.
My theory is Glasswire creates/checks these rules on boot? and because I have a long amount of history Glasswire is creating a lot of rules for older versions/programs no longer installed possibly?
I suspect I need a way to mass prune the Inactive Applications list possibly but I cant find a simple way to do that.
Does removing them from that list remove their history as well? I would want to keep the history but I just want to clean out old rules that no longer apply. Things like Dropbox updaters that change in version etc.


You could Exit GlassWire, go to your Windows Firewall control panel and “restore defaults” then reinstall GlassWire on top of itself using its “clear firewall” option to see if that helps. It should keep your history/settings besides your Firewall settings.

I exited, stopped the service and reset windows firewall. I confirmed there were no glasswire rules then I downloaded the newest version. I then checked the restore windows firewall settings and installed but sadly on startup (not restart) the same problem occurred. I think the cpu usage is caused by Glasswire working with the rules when it starts up as I can see the rules being created by refreshing the advanced firewall config (in total 2245 rules it appears on outbound)

At least now we know roughly where the cpu usage may be coming from, the mass of rules being created/checked on my machine on glasswire startup.


If you try a clean install, then keep GlassWire’s firewall set to “Off” does the problem go away?

try using free program called “process hacker” and you can get it on sourceforge web or simply google itl

this is a great program to see what thread, handle, ddl file, modules, file location, environment, services, and everything you need to know why that processes is taking up a lot of cpu. i use this as a advanced task manager and power kill the process.

i have a same problem as you as well - i noticed when i install the glasswire and my svchost is using more memory than before.

i hope this help you to understand why there large cpu usage on that process.


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Just to say I finally got a chance to clean install (or well I moved the database files in programdata\glasswire as I dont want to lose my history) and removed the firewall rules and there are no issues with the cpu problem when glasswire starts so I think its 100% to do with the history and creating those firewall rules.
We need a process to prune the rules/old app versions as it does seem to be it interacting with Windows Firewall that creates the issue, I do have a large history (over 1 year which I want to restore tbh) and it was creating nearly 3000 rules when it started.
When glasswire started firewall inside it was set to off, when I set to on the same processes started using cpu but it created the rules quickly and things went back to normal.

Hi @Ken_GlassWire
I just upgraded to the latest version and removed the inactive applications but sadly it appears this does not prevent Glasswire creating the 1000’s of firewall rules for older applications it appears.
Does removing the inactive apps affect firewall rule creation when firewall mode is turned on?


GlassWire does not make firewall rules for no reason.

GlassWire will only make thousands of rules if you have thousands of apps, and if that’s the case then GlassWire is behaving exactly as expected.

Please go to the GlassWire Graph/Apps tab and select the longest time interval you have (Unlimited, 1 year or 6 months). How many apps are there? If you don’t want to say you can email me privately.

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