Roon on macOS High Sierra 10.13.4 using 100% of CPU

I’m running Roon on a brand new MacBook 1.3 Ghz Intel Core i5 with 16 GB of RAM. I’m using a Spectra USB DAC for output. About 40,000 CD rips stored as FLAC files on an external USB hard drive (a brand new drive).

Roon sounds great. The music doesn’t stop or hiccup but I often get the spinning beach ball on the user interface and it’s very slow to update the album artwork. Running in Roon radio mode is a real pain. If I give thumbs down to a track it takes minutes to display the next pick. Activity monitor shows Roon often using over 100% of the CPU or Roon not responding. Nothing else is really running on the computer. The browser is using maybe 3% of the CPU.

Why is Roon burning so much CPU?

Is your library still being analyzed for audio? You can check and maybe post an image of the library settings under the settings options.

40000 Cd’s is a lot tracks…how many is it showing?

Just to clarify, it’s 40,000 tracks ripped from CDs. I don’t know how many CDs. I was using Squeeze Server for years and it had no problems. I’ve been using Roon for at least 6 weeks. How long does it take to analyze this many tracks?

Hey @JOHN_WILLS — Thank you for your report!

To start, may I kindly ask that you verify the following:

  • Since experiencing this behavior, have you tried rebooting your Core machine?
  • Can you please share a screenshot of Settings > Storage in Roon?

Thank you,

No, I didn’t try rebooting but I think I may have done a reboot for some other reason.
I have a screen shot but I’m not sure how to post it.

Thank you, @JOHN_WILLS!

Next, I’d like to propose a test that will hopefully give us some more insight as to when this behavior occurs:

  1. Reboot the Core machine.
  2. Check CPU utilization.
  3. Open Roon.

From here we will want to monitor CPU activity so we can pinpoint exactly when this behavior occurs. Does it happen right away? Does it happen once you start playing music?

Additionally, do you have any antivirus or firewalls on the Core machine? If you disable those do you still experience this behavior?


I’m not running any antivirus or firewalls on the MacBook. I shut down all the apps, rebooted, and started up Roon. Then I started up Activity Monitor to watch the CPU utilization. I’m leaving Roon running 24 hours a day playing “radio” from my collection. So far no problems. Roon is using about 18 % of the CPU. I’ve started up Chrome. It’s the only other app I’m really using.

I’m temporarily (3 - 4 months) living in Taiwan while I work as an Engineering Consultant. I will let Roon continue to run and see if the problem resurfaces. When I return to the USA I will be running Roon on some type of server instead of my MacBook.

Roon started exhibiting the same behavior. I clicked on thumbs down on the next track queued up for “radio” and the CPU utilization shot up to 100% and stayed there for 1 minute before the next track was updated. Then The CPU dropped back to 10 - 13 %.

Thanks for the additional details, @JOHN_WILLS.

Does this happen every time you thumbs down something on in the queue for radio? Does it happen with any other interactions? If it’s playing music and you aren’t interacting with Roon, does this still happen?


Yes, it happens every time I do thumbs down. It also happens if I skip to the next track. If I don’t interact with Roon it also happens when Roon switches to a new track.

Hey @JOHN_WILLS — I appreciate the clarification on that.

In the upper right-hand corner of the screen in Roon, do you see a spinner icon? This icon indicates that Roon is performing analysis on your library. If it is there you can click the icon to get more information about what work Roon is performing. If the icon is there, please click it and take a screenshot of the screen.

Thank you,

There is no spinner icon in the upper right, just a bookmark symbol and a search symbol. I rebooted again and it seemed to take longer than the last time before seeing high cpu utilization when going to the next radio track. I’ve let it run continuously for days. I think it was about 3 days before the issue popped up but I can’t be sure. I’ve been working a lot of hours so I’ve kind of lost track of time. Once it gets into this state it seems to stay there.


Thanks for the update, @JOHN_WILLS!

I think the next step here is to enable some diagnostics on your account so our technical staff can get some more insight into what’s going on here.

However, before I enable this feature, I’d like to ask for your help ensuring we gather the right information.

First, can you please reproduce the issue once more and note the time at which the error occurs. Then respond here with that time, and I’ll make sure we review the diagnostics related to that timestamp.


It’s happening right now. If I reboot and start up Roon playing radio It probably won’t happen for at least 24 hours. I have no problem rebooting or running Roon radio 24 hours a day but checking on a timely basis to see if the issue has occurred is not really practical. At best I could tell you when the issue happened plus or minus several days.

Why don’t you buy or borrow a MacBook running HighSierra, fire up Roon radio with 40,000 tracks, and wait a couple of days. I’m sure you’ll see the issue. I’ve reproduced it 3 to 4 times. My MacBook is bone stock. I basically bought it so I could run Roon for 3-4 months while I live in Taiwan working.

I’ll give you another clue. I tend to run apps full screen. I’ve noticed if I switch to the browser for a while then use cmd + tab to switch back to Roon the CPU utilization goes way up and it takes almost a minute for Roon to actually display on the screen. Weird huh? I’m not changing tracks, I’m not giving thumbs down, Roon isn’t changing tracks, I’m just trying to bring Roon to the foreground and Roon goes crazy burning the CPU. I can’t tell you the exact sequence to trigger the behavior with background/foreground switching but I think it’s a big clue. You need to put on your thinking caps!

I’m working up to 11 hours a day 5 days a week. The other 2 days I’m usually having fun in Taipei a long way from my MacBook. I’m 15 hours ahead of California. I never work from my apartment where Roon is playing. The only time I can check if the issue is happening is when I get home from work or in the morning before I leave. Some nights I come home and go straight to bed. Some mornings I have to leave as soon as I’m up. What I’m trying to say is I don’t always have time to mess with the MacBook.



My sincerest apologies about the difficulties here. I know this can be frustrating, but I want to assure you that we are 100% dedicated to getting you fully up and running here.

I have enabled diagnostics on your account and will be monitoring our servers for the report. I’ll be sure to update you once it’s received. I will then pass it along to our technical team for analysis and I will be sure to update you ASAP on their findings.

Kind regards,

Hey @JOHN_WILLS — Thank you for your patience as we continue to investigate.

In order to aid in the investigation, we are hoping to gather some more information. To start, may I ask that you please confirm the following:

  • Is your Core on an SSD?
  • Can you please share a screenshot of Settings > Library in Roon? This will allow us to see if Roon is still doing any analysis.

Thank you again for your continued patience and cooperation. We are continuing to investigate, and knowing the above will be a great help in doing so.


My MacBook does have a SSD. The FLAC files I’m playing are on an external hard drive (not SSD). The drive model is Toshiba HDTB410XK3AA 1TB External Hard Drive USB 3.0.

The Internet connection in my apartment was down for 4-5 days. It’s back up now. I’ve rebooted my MacBook and started Roon radio. I should be able to let it play continuously for at least 6 days. The issue should occur within a couple of days. I will let you know.

Not seeing the issue yet.

Hi I just checked my Mac mini (late 2012).
I have the same Sierra as you.
It’s a i7, 8GB Memory, SSD on 256GB and 1TB SATA.

Roon Server installed on the SSD.
When I’m playing Roon it’s not going over 10% and when I checked, the overall use of my processor it showed 1-2% was used and 1-1.5GB!

Love & Respect