High CPU Usage on Mac Mini 2018

Running into the same issue.

  • Mac Mini (2018)
    • Mojave 10.14.5
    • Roon 1.6 (build 416)

Roon.app pegs the CPU whenever the app is launched. Sustains 400-500% CPU on a 6-core machine.
The behavior of the app doesn’t seem to affect the CPU usage. Doesn’t matter if it’s idle or playing music.

Roon is operating in client mode only, talking to Roon server (linux) attached to the same local switch. At idle, no noticeable network traffic between the client on the mac, or the roon server+bridge on the linux host.

Problem is 100% reproduceable. Launch the app, and automatically spikes the CPU.
I’ve tried uninstalling and reinstalling the mac roon client, and the behavior continues.

Additional info: this happens on my Mac Mini, but the same build on my Mac laptop does not run into this issue. Same version of Mojave (10.14.5) installed on both machines. Seems to be associated with this specific Mac client, and not the back-end. Also, very light CPU usage on the roon-server running on Linux.

What additional details can I offer to help identify this issue?

I just started a two week trial and I’m experiencing the exact same issue.

macOS Mojave
Version 10.14.5
Mac mini (2018)

As soon as I launch Roon, all six cores are immediately pegged. Even if I’m just sitting at the login screen.

Hello @Dan_Backman and @Mike_deCock,

Thanks for the reports, I’ve forwarded this information to the QA Team for investigation.

Some further info that would be helpful:

  1. Have you been able to get Roon running at all on the computer in question?
  2. When looking at Activity Monitor.app, is it just Roon.app that is leaking CPU or is it the RAATServer process as well?
  3. Do you have any security or firewall software install on your Mac?
  4. Do you have any virtual sound cards or other audio plugins installed on your Mac?

Here are some diagnostic tests that would help us track down this issue:

  1. Disable the macOS system firewall, along with any other firewall software on your computer. To disable the macOS firewall, go to System Preferences > Security & Privacy > Firewall.
  2. Download and install the “Roon Bridge” package for macOS from the Roon downloads page. When Roon Bridge is running, are you able to connect to audio devices hosted on the computer while using a different Roon Core / Roon Remote?



  1. Roon actually works fine. I can browse my library and play music but the processor is pegged and my CPU fan starts getting noisy after a bit. (I have the Roon Server running on a different computer, BTW)
  2. It is both processes. Roon is pegged at approximately 370% and RAATServer at approximately 80%.
  3. My Mac Firewall is turned off.
  4. I don’t have any virtual sound cards or audio plugins. My list output devices are:
    a. Mac Mini Speakers
    b. USB Audio DAC
    c. 24M35 (HDMI Audio of my monitor)


  1. The system firewall was already disabled.
  2. With Roon Bridge up and running, I can connect and play music remotely. The CPU utilization is normal running the Bridge.


  1. Roon appears to work correctly even though the CPU usage is high. Same CPU usage if I am streaming to a remote bridge or playing the music to a local sound device.
  2. Roon.app is between 400-500%, RAATServer is pegged around 98%
  3. No additional security software is installed. Firewall is disabled.
  4. No audio software or devices are installed other than Roon.app and iTunes.app


  1. Firewall already disabled.
  2. RoonBridge works correctly from a remote host.
    Note: when I run RoonBridge.app, and close the Roon.app application, I now see RoonBridgeHelper stuck at 400% CPU. When I relaunch Roon.App, I now see both processes consuming > 300% each. RAATserver is still at > 80%

I can also run a process trace in Activity Monitor and send that to you if you can provide me with a direct email address to submit the data.

Interesting to note that Mike_deCock and I have several things in common:

  1. Mojave (10.14.5)
  2. Mac Mini 6-core (machdep.cpu.brand_string: Intel® Core™ i7-8700B CPU @ 3.20GHz)
  • the high CPU usage does not seem to happen on my quad-core MacBook Pro (2015)
  1. Display audio devices attached
  2. Roon.app is connected to a remote Roon server

Audio devices:

$ system_profiler SPAudioDataType



          Manufacturer: Apple Inc.
          Output Channels: 2
          Current SampleRate: 48000
          Transport: DisplayPort
          Output Source: LED Cinema Display


          Manufacturer: Apple Inc.
          Output Channels: 2
          Current SampleRate: 48000
          Transport: DisplayPort
          Output Source: LG HDR 4K

        Display Audio:

          Default Input Device: Yes
          Default Output Device: Yes
          Default System Output Device: Yes
          Input Channels: 1
          Manufacturer: Apple Inc.
          Output Channels: 2
          Current SampleRate: 48000
          Transport: USB
          Input Source: Default
          Output Source: Default

        Mac mini Speakers:

          Manufacturer: Apple Inc.
          Output Channels: 2
          Current SampleRate: 48000
          Transport: Built-in
          Output Source: Mac mini Speakers

Here’s an interesting observation. If I have the Roon Bridge Running before I launch the Roon app, I don’t experience the high CPU usage.

Hello @Mike_deCock & @Dan_Backman,

Thank you both for the observations, I have added this information to the QA ticket. I will be sure to follow up when QA has made an assertion, I know they are actively working on this.


Hello @Dan_Backman & @Mike_deCock,

If you go to your ~/Library/ folder, you should see a folder named “Roon”. Could you try renaming this folder to “Roon_old”, then restarting Roon and reporting if you see any differences in behavior?


Hi John,

I renamed the Roon folder as instructed and restarted Roon. It created a new folder and the CPU usage spiked immediately.

Edit: This was with the Roon Bridge turned off. When it’s on, I don’t experience the high utilization.

This did not solve the problem. I moved the directory as you suggested, and the app asked me to acknowledge the terms and conditions and reselect my roon server.

Once the app launched, I am having exactly the same problem with high CPU utilization as before. No change.

Any updates on this? The symptoms seem 100% consistent on my client, and are easy to replicate. Is there anything else we can do to help troubleshoot this?


Hello @Dan_Backman,

Could you use the “Sample Process” feature in Activity Monitor to save logs of Roon as well as RAATServer when they are in this broken state? Once you have saved the logs as text files, please upload them to a service like Firefox Send so we can pass them along to the development team.


Hello @john ,
I have the same issue (Mac Mini 2018 + very high cpu load)
I created a logfile and sent it via Firefox send to your support (contact panel).
But I think the 24h expired.

How can I contact you?

Hi @Tim_Surber,

Thank you for your interest here. I have just followed up via private message for next steps and this message should appear as a green “1” in the top right-hand corner of this site.


The high CPU usage issue on this 6-core Mac Mini seem to have been solved by the latest update to macOS (10.14.6)

For the other people on this thread, can you confirm that this OS update seems to have fixed the issue?

No, still the same for me.

10.14.6 update does not resolve issue on my 2018 mac mini

Looks like you guys are right. While the update made things better, if I leave the app running, it will eventually get back into the same high CPU state (even after the 10.14.6 update). Looks like there is still something going on in the Roon.app

I was strongly considering upgrading my mac mini to a 2018 one. Is this issue present in all of them or is it only noted in an unlucky few?