Mac OS High CPU Usage

Hi @Philippe_Morali,

I understand. We have seen reports that toggling the WiFi even when not in use temporarily resolves this behavior, so if the issue re-occurs I would suggest giving that a try, as it would be faster than rebooting the entire PC. We are of course still investigating this behavior internally on our end as well.


Understood and thank you, will keep that in mind.


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Recently upgraded from a 2012 model iMac with HDD to a 2019 model with SSD. Roon runs from a headless Mac mini with an SSD. Having never had issue with high CPU use from Roon before, it has started doing exactly what others describe.

Tried toggling wi-fi (which is never used as the iMac has an ethernet connection) and sure enough, the CPU usage instantly fell back to normal levels. It’s very odd, but hopefully give the engineers/technicians something to go on in trying to resolve this issue.

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Interesting info!

I have never experienced high CPU usage on my MM, but then I have never turned on WIFI on the MM.

@noris, Any update on your front on this issue.
I still see the same behavior occurring on a weekly basis, on average.
Thank you

FWIW, I am running the UI on an iMac Pro and WiFi is not used on this device and I still have the problem. I have to say that it has been significantly reduce over the past month or so. I am currently running MacOS 10.15.4 The roon software on this device is 1.7 (build 528). The core is running on a Nucleus +.

I just had to quit roon on my iMac Pro again due to high CPU utilization. We are coming up on the one year anniversary of this problem. Lots of folks have forwarded information and it seems common enough so that you should have been able to replicate it in you lab. Can you confirm if it has been replicated?

Hey, where is support??? I don’t seem to have even had a reply on this. It seems such a fundamental problem, experienced by many from the number of posts, should have been resolved by now.

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I have only RoonServer running on a 2020 i7 iMac, 16GB RAM, latest MacOS. No issues - is there a link with Roon (instead of Server) here? Roon is doing graphics, Server is not. Is the issue there?

The issue does not (appear) to be the server as mine runs on a Nucleus +. I am talking about using the roon app on my iMac pro. The problem existed on that machine also when I ran the UI and the server on the same machine so that indicates to me it is the UI portion.

All that said, there seem to be a lot of entires about this and it has gone on for over a year. The way I feel now, I wish I had not purchased Roon hardware and a lifetime subscription.

One addition. Rebooting my machine in very inconvenient as I have multiple desktops and setting everything up again is time consuming. Rebooting seems to be the only solution to the problem that I know about.

@john - What is the other topic. I have been making additional entires here. This has been over a year. When will this be fixed?

this is another one for CPU: High CPU Usage on Mac Mini 2018

Not sure if there is a specific one about CPU, at least that one is the one with the most views, a lot of threads in the forum on CPU usage.

I have another one for GPU: macOS Catalina interface laggy randomly while running Roon (High GPU usage randomly, Roon idle 20% GPU, sometimes up to 99% usage)

I had a similar issue that is unrelated to Roon a few weeks ago. I keep my 2019 MacBook Pro connected to a Thunderbolt Display (built-in ethernet connection) most of the time. Normally I just turn the WiFi off knowing the WiFi is not needed. I somehow forgot to do so and for about a week the fans would spin up and stay up until I restarted. It did not matter what I was doing, including nothing, those fans were at full speed. I had come to realization a complete restore was going to be necessary until I noticed WiFi was on. I turned it off and now the fans rarely turn on. Might not be your issue, but I figured I’d offer it up as a possibility.

I’ve had similar ongoing issues with high CPU usage on a 2018 Mac mini running Mojave, i5 processor, 32GB ram, ethernet connection only. Setup Roon Core on the Mac when it was new May 2019. Initially launching Roon would spike the CPU for a few minutes and then level off, typical for graphic intensive databases rebuilding cache files. Persistent high CPU usage started showing up in August 2019, 200+% CPU load on launch after startup of Mac. Wouldn’t drop to normal levels. Had to quit the app. Sometimes it would run up the CPU just sitting idle for no apparent reason.

I’ve found a fix and a possible reason for the issue. When the processor starts ramping up and staying up, turning on wifi, enabling network interface en0, even if it’s just for a second before turning it off, stops the high CPU usage for me. It seems like a system call in Roon is being made to en0, and if it doesn’t receive a response, the CPU load maxes out. While having 2 active network connections is not best practice, I’ve settled for having both an ethernet and wifi connection active. Since this I haven’t had a single high CPU instance with Roon. YMMV

I think the issue of WiFi may have come up on a thread. In my case, I don’t use wifi on my desktop so I don’t think that is it - at least in my case.

My main point is that this is not a new problem and has existed for some time. @noris has not responded, nor has anyone else from support. I tagged him her just so he cans see this string is alive. If the solution has been posted elsewhere, perhaps he can post it.

I have this same issue happening on my Mac Mini as well. I have the same config as you except, I am running Catalina, I also never have the wifi turned on as well. I did turn it on and my CPU utilization immediately dropped as well. I then turned it off and the utilization remained low.

I have not beed a roon user very long, but very concerned this thread has been going on for over a year. I will add I don’t experience this on my older Macs.

Hello All,

Please see Dylan’s update on this issue here:

@noris Any updates? I have given up trying to use Roon on my desktop. After all this time, I think it is reasonable that we get an update every week or so.

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@support right, weekly updates would be great instead of having to ping you.