Albums suddenly missing tracks

Issue description:

I’ve added a few new albums to jellyfin and then triggered a rescan of the jellyfin source in Symfonium. After the sync was done the new albums appeared, however since then all the albums in my library that I checked were missing tracks. I did not recognize a pattern. I once again initiated a sync that seemed to finish, however the tracks were still missing.

To test if the scan had gone wrong I removed the jellyfin source, readded it and let it scan everything anew.
That seemed to work for half a day. All I’ve done since is listen to music. I haven’t initialized another scan, however earlier today I noticed that tracks are once again missing from every album.

The only semi similar issue I found in the forum was this.
However I do not have files larger than 2GB in my music folders. The largest is a flac song with 1.5GB and all tracks showed up fine after the initial scan, so I doubt that’s the reason.


Here’s a log from the time when I noticed that the songs are missing again, it looks like it is syncing, but inside the app the sync indicator does not show an active sync.
debug.log (24,3 MB)


No active sync:

Album in the jellyfin desktop client with all tracks:

Album in Symfonium missing tracks 3, 5, 6 and 9:

I just checked how many songs it still has:

462,479 compared to the 790,105 that the jellyfin desktop client shows is quite the difference.

I would need a log during sync to see what Jellyfin do but with such a large library it might be complicated.

Is your server remotely accessible?

In theory syncs are secure and are not applied if there’s issues.

And in the logs I can see that there’s a sync started but Jellyfin is really slow to answer.

2023-07-14 12:42:12.052 T:Jellyfin
Music sync needed (790105 / 462479 / 462479): true

So there was an issue in previous sync but I will need logs when it occurs to understand.

It is now, I’ve added it to my reverse proxy.

A few hours later the tracks reappeared after I manually started a resync a few times. Let’s see how long they last this time. Is it normal behaviour for tracks to disappear from the database during an automatic sync?

That does not surprise me. When I open up Jellyfin (either in a browser or the desktop client) it takes 14ish seconds to fully display the starting page with all the “recently added” etc. stuff.
Jellyfin really doesn’t like my amount of music. When I only had my movies and tv shows added it was very snappy.
I’m considering to split jellyfin into 2 instances, one for movies, documentaries, tv shows, etc. and one for the music alone, which is only used via the API. That should at least alleviate the response times for the movies and tv shows a little bit.

As said no in theory unless Jellyfin bugs (Possible) then Symfonium should abord the sync in case of errors.

That’s why even if will be hard I’d need the logs for when it happens.

About Jellyfin UI, yes for music the ui is slow :frowning: I’m at 350K songs and it"s already a pain. But never had a sync issue.

Do you often add songs? Sync should not start unless there’s new songs. So if you do not change your content and sync auto start there’s something odd.

Pretty much daily, I manage the combined music collection of my entire family. However I don’t manually initialize scans for jellyfin. Jellyfin scans all my libraries once every 12 hours. Do you think I should increase that interval to 24 hours to reduce the probability of problems?

I’ve also set up my sister’s smartphone (OnePlus 8T) with Symfonium and Jellyfin 2 days ago and for her no songs have gone missing yet (she loves the app). Maybe my smartphone hates me. I’ll report back if it happens again. She also just got a new smartphone (Pixel 7 Pro) so I’ll see if that behaves differently than my OnePlus 7T or her old OnePlus 8T.

There should never be any sync issue.

Maybe sync during the Jellyfin scan makes Jellyfin return invalid data.

Only logs when it fails can tell.

I’ve done some further testing and am pretty sure that’s the case.

The initial scan goes well and all tracks show up afterwards.
However after a subsequent jellyfin scan (after adding or changing something), an automatic sync in Symfonium is also triggered (maybe before Jellyfin had time to finish) and that’s where tracks go missing.

I’ve tested that by removing automatic scans in Jellyfin, triggering manual scans (after adding/editing something) and watching what Symfonium does on its own.

I also recreated it with the new Google Pixel 7 Pro of my sister.
First sync, all tracks there, automatic sync after Jellyfin scanned: 450.000 tracks missing.
Next sync with Jellyfin not having scanned in-between: all tracks are back.

If you want logs I can send you credentials for my jellyfin server.

Once you’ve scanned all tracks you can send me a message, I’ll add a few albums and trigger a jellyfin rescan and you should get logs showing you what you need to find the problem.

My hunch is that a delay for automatic syncs in Symfonium might solve this issue for large libraries like mine.

Jellyfin is the source of Truth if it returns invalid data there’s not much I can do and random delays won’t fix anything.

For now you can disable library auto sync in settings and sync when needed.

I’ll try to see if Jellyfin expose a status telling it is currently scanning.

But if you sync the 450 k after Jellyfin is finished scanning then not sure how I can detect that it returns invalid data …

Thanks for letting me test the beta version, your changes seem to have fixed my issue. I’ll verify tomorrow by letting my sister run a sync on her phone as well to make sure but it looks very promising.
Thanks a lot!