Roon library constantly rescanning causing instability (ref#JM43LO)

Support
1

Hi! What’s not quite right with Roon?

· None of the above quite fits

None of the above quite fits

· None of these quite match

Tell us what's going on

· My library keeps being rescanned all the time - after a while Roon becomes unstable

Tell us about your home network

· Telenet Router > English Electric 8-switch

2

Hi @Peter_Neirinck, welcome back to the community.

Frequent rescans usually point to something in the watched folder path, storage, or network share that Roon keeps seeing as changed. Since your server is on a Telenet router with a switch in the path, a couple of things would help us narrow this down:

  • Where is the music stored, local disk or a network share?
  • Are the files on the watched folder changing, moving, or being touched by any sync, backup, or antivirus software?
  • When the rescans happen, does the watched folder live on a device reached over the network, or on the same machine as Roon Server?
If your music is on a network share, our [url=https://help.roonlabs.com/portal/en/kb/articles/networking-best-practices]Networking Best Practices[/url] guide covers the kinds of network and share configurations that can cause repeated library activity like this.

If you can share the answers above, we can take the next step from there. We’ll also enable diagnostic mode for your Roon Server, if you could please bring it online, that will help us better understand what might be happening behind the scenes.

Thank you!

3

Hi

Music (watched folder) is on the internal SSD of my 432EVO model Aeon streamer/server/ripper-machine. This server serves as Roon Core. Files are untouched by any process. The rescanning happens always without any stop, unless I disable the watched folder of course. My machine will be online in 15 minutes from now. Please mind that as a hifi dealer I need this machine for demo purposes (for which I use Roon most of the time…).

Thanks,
Peter

4

Hey @Peter_Neirinck,

Thanks for the heads up! In the future, please know you have access to our separate, dealer support channel:

dealersupport@roonlabs.com

Thank you for bringing the server online, the diagnostics came through and they tell a clear story.

Your library isn’t just rescanning periodically; Roon’s initial scan of the watched folder is failing partway through and restarting itself every half-second, continuously. It never gets to finish, which is why the library never settles and the server becomes unstable over time. The internal error is a “collection was modified” fault, which happens when the contents of the watched folder change while Roon is in the middle of reading them.

That’s the key clue. Even though you’re not touching the files yourself, something on the 432EVO appears to be writing into the music folder while Roon scans, a background process such as cover-art/thumbnail generation, ripping, or the unit’s own indexing/database service. We can see a lot of generated small_cover.png / large_cover.png files in your album folders, which points in that direction.

A couple of things would help us pin this down:

  • Does the Aeon run any built-in service that writes into the music folder, automatic cover-art generation, CD ripping, or library indexing? If so, it may be worth checking with 432EVO whether that can be paused or pointed away from the folder Roon watches. This is the most likely fix.
  • As a quick test, could you point Roon's watched folder at a small folder of a few albums that the machine definitely isn't writing to, and let it sit for a few minutes? If the constant rescanning stops, that confirms live changes to the folder are the trigger.
Separately, the scan is flagging a few files as damaged that are worth sorting out regardless: the Tracy Chapman – Our Bright Future album (Roon can't read these off disk at all), the track Dire Straits – On the Night – "You and Your Friend," and the Enmanuel Alexander – Off the Cuff DSF files. Re-ripping or replacing those is a good idea.

If you can try the test above and let us know about any background processes on the Aeon, we’ll take the next step from there. I’ll leave diagnostics enabled on our side in the meantime. :+1:

5

Hi Benjamin

I have been able to solve the problem by searching the music folder for all .png files and removing them. I also removed all .jpg files unless named “folder.jpg” or “cover.jpg”. Now the constant restart of the scanning has stopped. I forced a rescan and it terminated properly.

There was no process on the music folder running on the server. Now it’s only a bit of a mystery to me where all of those .png files came from. I never put them there. So maybe it is the ripservice that sometimes does that, or could it be that Roon itself puts any album art on disk?

Thanks for helping me out.

Best regards,

Peter

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Oh, the problem restarted in the meanwhile. The PNG and unwanted JPG files are still deleted. So there has to be something else going on. May be the database itself is corrupt? The corrupt files you were talking about (such as the Tracy Chapman album Our Bright Future and others) no longer exist on disk, but maybe they are still present in the Roon database index?

7

In Library/Skipped Files I found another folder with DSF music files. I deleted that folder, restarted my server and Roon, but the problem persists.

8

Will be offline now until this evening. But the server is still running.

9

Thanks for the updates @Peter_Neirinck! After reviewing a fresh set of Roon Server logs after the work you’ve done, we can now see Roon’s initial library scan seems to crash and self-restarts every ~1 second, forever. The library never finishes importing.

More importantly, we’re now seeing that the scan never gets past the Meatloaf “Top40 Collection” (Cd_1 / Cd_2) folders. Those two discs share one album id (67:0) and one cover.jpg that keeps getting re-queued as an aux-file add, and that add is the concurrent modification that kills the enumeration.

See if you can:

  • Isolate the Meatloaf Top40 Collection folder. Move Meatloaf/Top40_Collection_Cd_1 and Cd_2 completely out of the watched folder, then force a rescan. If the scan finally completes, that folder is confirmed as the trigger, likely a multi-disc/shared-cover edge case. This is the single most targeted test and directly matches what the logs show.
  • If that doesn't clear it, do the small-test-folder check we already suggested (point the watched folder at a handful of clean albums) to confirm the scanner works at all, then reintroduce content in chunks to bisect.
Afterwards, be sure to head into your Roon Settings > Library > Clean up Library. This will fully remove the stale entires you’ve removed from your watched folders above.

We’ll be monitoring for your reply, thanks Peter!

10

Hi Benjamin,

Removing the Meatloaf & Friends double album, plus cleaning up the library, did not solve the problem.

So then I disabled the watched folder containing all my local music. Afterwards I added a new watched folder with the subdirectory “Various Artists” from my music library, which is still a big subdirectory containing +300 albums. This solves the problem, at least for now. I will look again if anything weird happens tomorrow.

Thanks Benjamin.

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Hi Benjamin, a question that comes up is why Roon read DSF-files before (I have many albums in DSD-format, which are actually DSF-files) but in the Skipped Files sometimes a folder with DSF-files was reported. Any clues? Should I remove all DSF-files from my music folder and if so why?

Best regards,
Peter

12

Hey @Peter_Neirinck

Good news on the DSF question: no, please don’t remove your DSF files. Roon fully supports DSD/DSF, and your logs confirm the vast majority of your DSD albums imported perfectly.

Only one album is being skipped, Enmanuel Alexander, “Off the Cuff – Live at Meadowlark.” Those files are flagged as audio_stream_format_not_supported because they’re encoded as DSD256 in the 48 kHz rate family (12.288 MHz).

Roon supports the standard 44.1 kHz DSD family, which is why your other DSD256 albums load fine but these don’t. Re-ripping or converting just that one album (to a 44.1-based DSD rate, or to FLAC) will clear it. That’s what was reappearing in your Skipped Files, it’s harmless and completely separate from the rescanning issue.

On the rescanning itself: your fix was the right one. The logs show Roon’s initial scan of the full music folder was colliding with its own live folder-watching and restarting endlessly, an internal edge case that a large watched folder triggers, not anything you were doing to the files.

Since you narrowed the watched folder to “Various Artists,” the scan has completed cleanly and the library has stayed stable with no further errors. If you’d like to bring the rest of your library back in, the safest approach is to add it in a few separate watched folders rather than one large top-level folder. I’m also flagging the underlying scanner behavior to our team.

Let me know if you’re able to get your full library back by running through the above. :raising_hands:

13

Hi Benjamin

Yes, it seems that cutting up the library into several seperately watched folders solves the problem.

I have now added one last folder with DSF-files only. No restart of scanning occurs at the moment.

Thanks for all your research and help!

Peter

14

Hey @Peter_Neirinck

Glad to hear that helped. It’s good news that splitting the library into separately watched folders has kept the rescanning issue from coming back, and that the DSF-only folder is staying stable for now.

We’ll go ahead and close this one out. Enjoy your music, and thanks again for working through all of this with us.