Which UPnP server software are you using? Mosaic displays what the server sends it. With some server software the data that may be sent from it to fulfil Mosaic’s command may not be what you are expecting. See this FAQ:
We are using MinimServer. All software current, no changes in set up.
Thanks. That wasn’t the answer that I was expecting 
. I think you will need a response from Andrew or James of dCS to take this further.
Yes hope so @Andrew asked for information 3 days ago so fingers crossed there is a reason for this truly bizarre behaviour by Mosaic - one thing’s for sure shouting don’t do that at the ipad doesn’t have any effect!
Wondering if ios 13.5 is causing problems
Is that Minimserver 2?
I had a similar experience when going from Minmserver 0.8 to Minmserver 2.
Just a hunch…
No we’re still on 0.8 It was installed years ago by a friend who unlike me is computer literate. He had made his own adjustments to the settings - trees I think he called them - which work very well and we have no desire to change.
Seeing complaints about ios13.5 is raising our suspicions. My ipad is sitting with the latest iteration 13.5.1
I too am running 13.5.1. No problems whatsoever with MinimServer v. 8.5.4. However I currently have no UPnP playlists. If I have a bit of time ( what do I mean “if” during lockdown?) I will create one and see what happens. Logically as Mosaic only reflects what MinimServer sends it my dumb and uninformed thought is that this might be a server issue.
I know that this would take time to do but have you considered refreshing MInimServer given that your installation seems quite old? Could the settings selected by your computer literate friend have corrupted over time? Could you get him to take a look at it ( subject to social distancing of course)? However maybe you would now need to install MinimServer 2. I am leaving that one until I have to.
On the other hand, this could be merely coincidental. I also did a bit of rearrangement in my NAS library, improving my library by using JRiver’s capability to tag files. Afterwards I rescanned my library via MinimServer/MinimWatch. And new playlists works just fine.
No iOS involved here, just Android and Windows 10.
I will also keep my eyes open and report back to you if the problem occurs again.
No, I was wrong - I just made it happen again!
I rescanned my library with MinimServer and then went to my main rig and loaded a Mosaic playlist that I created a week ago (37 files from my NAS, nearly 3 hours of music).
I first saw the first let’s say 10 entries, then suddenly they changed and approx. half of the items changed names. When I play the list the new files will occur in the Mosaic play qeue.
Very surprising! Anyone got the same result?
It seems like there is something happening in the communication between Mosaic and MinimServer. To me, it looked like Mosaic remembered the original playlist at first but then within a second got new information from MinimServer and changed some of the content in the playlist.
Well Goran it has happened to me again tonight. Two playlists I spent some considerable time assembling, corrupted. This is an utter waste of time.
Still nothing from dCS?
Not yet, Archie!
I just posted the issue over at MinimServer support. We’ll see if they have some suggestion…
I really long for the App we had when we had our Aurender streamer a few years back. It just worked.
I got a very fast response from MinimServer author Simon, saying:
“It looks like dCS Mosaic is storing UPnP object IDs for the tracks in the playlist. These object IDs can change when MinimServer does a rescan. In this case, you would either get the wrong track for the playlist entry or no track at all.
There are other approaches for storing playlist tracks that are less likely to return the wrong track when the playlist is reloaded. I will contact dCS to discuss this.”
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A useful response from Simon Nash. If correct that would suggest that a fix may have to await the next Mosaic update at the soonest.
That sounds promising - I look forward to dCS replying to you. Thank you for pursuing this with Simon Nash.
This is a known issue with Playlists sourced from UPnP and is a side effect of the process we use to refresh track metadata and artwork. We’re investigating solutions and there’s a chance that we’ll be able to sneak a fix or workaround into the next version of Mosaic.
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Thank you, Andrew! I hope you will be successful in this endeavour!
Best regards
Göran
A known issue? OK. Yes a solution would be most welcome as playlists is a feature up until now I used a lot. Until I posted about it here I hadn’t encountered this behaviour before - our Rossini must be around 3 years old now. Our playlists are always from the NAS so upnp is the problem then. That’s good to know as there’s no point putting together any more till this is fixed.
Yes. We discovered the problem in March 2020.
The new playlist mechanism (as of Mosaic 1.1.0) periodically refreshes track metadata so that what is shown in the list is always current. This is breaking with some UPnP servers as we aren’t being given ID information that remains constant through all rescan scenarios. So in other words, the track identifier that we’re given today will get reset with the next rescan and will likely end up being assigned to a different track. We may end up removing the refresh mechanism for UPnP tracks which would make it behave like the old Rossini app.
Playlists will never be perfect with UPnP as there’s no surefire way to fingerprint a track. Any change to track metadata and/or location on storage will likely cause the server software to see it as a completely new file and that will likely break any link that we’re able to establish. This is one of the fundamental limitations of UPnP and one of the reasons why I’m a big supporter of Roon for those who make heavy use of playlist features from their local library.
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