100% CPU load on Windows on Zerotier Service start - no DNS working


had this issue for so long, even with latest Zerotier 1.8.9 on Windows.

As soon as i start the Zerotier-Service the CPU will go up to 100% (from 20% before).
DNS will not work for about 30 seconds anymore. No web-browsing possible anymore. I am only connected to 3 Nodes. Back to normal after those 30 seconds.
Same on stopping but only max 12 seconds.
Intel Core i5-8265U.
I can reproduce that anytime. Shutdown, reboot, sleep. Manual stop and start service.

thanks for Zerotier!

Any idea?



Any idea? Which information do you need to find the problem?


@zt-grant would be awesome if you could help here. Thanks!

Similar issue here. Everything works here, but my notebook get super warm/high CPU usage when ZeroTier is running (NOTE: it is the DNS-Client service host that uses a LOT of my CPU, not the ZeroTier directly, but as soon as I stop the ZeroTier, CPU usage drops to normal levels).

I must admit that I am connected to a handfull networks, but still I was not expected such a power consumption.

Is there any solution?

Same here with FreeBSD based firewalls (OPNSense).
Zerotier eats one cpu fully and caused a lot of bogus traffic which eventually kills the zerotier network due to serious packet overflooding.
Reverting back to 1.8.6 and everything is works fine again.

Are you guys connected to more that one network? i start having this issues on three windows machines. As soon the client is connected to more than one zt networks the cpu load goes crazy and windows shows phantom traffic on the process itself.

Exactly that. Right now i am connected to 4 networks. All different subnets. So no loopbacks.

Do any of your networks address spaces overlap with your local LAN’s address space in anyway? All I can think of off the top of my head that could cause this. My personal machine runs windows and is connected to several networks and I’ve never come across this issue

Please run zerotier-cli dump on your machines while they are experiencing the 100% cpu issue and direct message the file to me.

you might need an admin prompt/sudo/root

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