ARC crashes iPhone or Freezes while Playing a local song

I installed ARC on core and iPhone as instructed. Upgraded from 1.8. It connected to the network without issue. It pulled up my library without issue. I searched for a band. The app returned search results and then crashed. I relaunched app, downloaded a song. Started to play the song. I searched again, clicked on the artist option, it returned results and then the results page then started blinking as if the table view cells were being re-loaded over and over again quickly. The app is frozen. No button is operational, no action can be taken. I relaunched the app multiple times. No success in fixing the issue.

500,000+ tracks

Roon 2.0 build 1128
Mac iMac, OS 12.5.1, 16GB RAM
Synology 2414 RP+
USB to wired network on both ends
NETGEAR ProSAFE 24-Port Gigabit PoE Smart Managed Switch
Synology has WFS enabled, SMB3, per another post’s suggestion

Network configuration/topology:
The mac is available on the wireless network
The synology is cabled into the NETGEAR ProSAFE on the network
Roon core server sits on the iMac.
Roon ARC app sits on iPhone Xs.
All UniFi endpoints are usb wired from the central controller.
There are no repeaters or extenders in the audio part of this system as they are not needed for audio here.
There is powerline conditioning, separate circuits, power outlets etc.

Hi @AD_Music,

I appreciate you bringing this issue to our attention, and please accept my apologies on behalf of the team that it’s taken us so long to reach your request for support in the queue of ARC-related issues.

After looking through initial diagnostics, the issue does seem to likely stem from the size of your library, which appears to be nearly half a million tracks.

In order to make ARC work and to support operation with poor or limited connectivity, Roon needs to synchronize information about your music library onto your mobile device. While the data synchronized is much more compact than what is stored in the Roon Core, for this large of a library it is likely still too big for a mobile device.

Aside from limitations in device performance, there are also restrictions on resource usage imposed by Apple and Google which make this scale of data transfer, synchronization, and storage impractical within a mobile app.

It’s unlikely you’ll be able to reliably use ARC in its current implementation (particularly on-the-go in the variable connectivity conditions of the real world) with a library of that track count.

That said, there are a few discrepancies between your initial report and diagnostics that I want to clarify:

  1. Are you using this iPhone as a Roon Remote, as well as for ARC?
  2. Can you please clarify if you’d successfully been able to configure port forwarding with ARC in the Roon → Settings page?
  1. It has the Roon app on it, but I was not using it as a remote. I am not sure if it was even synced to the core.
  2. Yes, port forwarding worked automatically.

Yes, if you are actually syncing all the data to the app on the phone I can see how this would be problematic. Is there a workaround like setting up an additional smaller library (not sure if Roon can do this)?


That is a great idea and should be a feature request.

If 500K tracks is too high for Roon Arc, then can you advise on the actual threshold?

Is 350K too high?


Hi @Robert_Philpott,

There’s no hard barrier, but the team finds a natural limitation starts to assert itself in the range of 300-600k tracks. Of course, this depends hugely on the phone and the file qualities of the tracks. 400k low-quality files might still work; 600k large DSD files very likely won’t sync at all.

Zooming out, how ARC performs (and whether it works at all) with extremely large databases is a delicate balance between three factors:

  1. The limitations of the Core (storage, memory, etc.)
  2. The limitations of the mobile device (storage, memory, etc.)
  3. The limitations imposed on the network for synchronizing a large stored library. This includes upstream/downstream connectivity for LAN and mobile network, obviously, but also the limitations imposed by Apple and Google mentioned above. This last factor is often overlooked when users consider their setups and whether or not to rely on ARC out-of-the-box.

If a user doesn’t have a library of over 500k tracks, in my experience, it’s worth attempting to sync with ARC if you believe your phone has the storage and reporting your issue to the team in this category on Community. We’ll be familiar with known errors, and can help identify if your issue is actually due to library size or something we can perhaps more easily resolve.

There’s a feature request for external storage enablement on Android devices here, as well: ARC: Support External Storage for Android (SD Card)

That’s interesting. I was wondering why ARC runs on my iPad Pro 12.9 (2020) flawlessly, whereas it’s unusable on my iPad Pro 9.7 (2016). The old iPad has only 2 GB RAM, the newer one 6 GB. On the old iPad music begins to stutter after short time and ARC freezes completely. I have 162k lossy tracks in my library. Btw. Roon Remote runs on both iPads without any issues.

Wonder if anyone is successfully running ARC on an iPhone 13 or 14 pro with a very large library?

What size would that be?

My iPhone X works fine as remote, but ARC has been unstable/unusable. 270k tracks, some higher rez but predominantly CD rez. Stops playing and usually crashes the app when playing the first song. I’ve never had a session where everything went as expected.

Today was likely my last attempt for a long while. Not worth the frustration. Back to Radio Paradise, sigh.

As defined by Roon above 300,000 - 600,000 tracks and above. Mine are all lossless just about.

I noticed the above post yesterday and gave it a try - ARC seems to be working as expected on my iPhone X now.

If you’re still having issues and haven’t already tried this, maybe give it a shot.

Replying to keep this thread alive. I have an iPhone 13 Pro Max and experience all the above. I’ve replied on other threads as well just so I can follow along and get an answer eventually.

I too have a large library of FLAC files, so I understand the syncing issues, but if there was a lower threshold would make this work better, I would gladly try it.