Mosaic dosen't find new album in NAS

I downloaded an album from PS Audio today and placed it in my NAS. I can see it there, Roon can see it, but dCS Mosaic doesn’t. What should I do?

Hopefully this will be simple to solve.

You have downloaded it but that only means that it is in your local storage. For Mosaic to find it ,its details also need to be scanned to your server software ( which I presume is MinimServer) so it can be located. So you need your server software to rescan. You can find this as an option in MinimWatch. Other software will have a similar option.

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I have added dozens of downloads to my Synology NAS without doing anything else and it has not been a problem. Has dCS changed the software? I don’t use or know anything about MinimServer.

This is recommended by dCS for UPnP via Mosaic.

There is nothing new about this as Jonathan indicates. Please see:

The need to scan new items into the server software is normal as control points like Mosaic reflect the server software. Otherwise everything will be random, as can be the outcome of certain commands.

MinimServer and MinimWatch are available as freeware. However the former has a licensed version which has additional features such as the ability to change or include search features. in the context of a dCS system it is inexpensive.However you can try it out for free initially. Different versions are produced for the brand of NAS you have.

MinimWatch controls aspects of MinimServer. It is an easy way to request rescans. It s installed on your computer ( on the same network as your NAS.), If your computer does not already have Java installed you may need to have this.


When you add albums to a folder that is being used to store music for a UPnP server then - as Pete has said - the UPnP server needs to scan the files to add them to its library … browsing folders and files directly via your computer on a network (using protocols like SMB normally) is not the same as browsing music via UPnP - which is more akin to going to the desk and asking a librarian what books they have in their library instead of being allowed to rave through the shelves yourself.

UPnP servers have different ways of triggering a rescan - sometimes they will simply rescan when told to do so, sometimes they will rescan on a schedule (perhaps - say - every morning at 3am or on some configurable schedule or whatever complexity the UPnP software authors deem to add - say - every third Tuesday of the month during summer but only when the weather is good), sometimes they will do an automatic rescan on first starting up after a reboot or sometimes they will try to monitor a folder for “changes” and rescan on any changes to the folder structure (this is actually not as handy as it sounds as if you are doing things like tag editing or copying new music into the folder then you can end up with lots of unnecessary and even failed rescans as the UPnP software tries to rescan files that you are working on and have “locked” because you have them opened for updating).

A UPnP Client (such as a dCS streamer) does not have any influence on how and when a UPnP server rescans its source library - all we can do is ask for the state of the UPnP servers library at that time.

What UPnP server are you using? Perhaps that’s a good place to start as then we can take a look at the documentation for that UPnP server and find out what triggers a rescan but usually files will “appear” over the 24 hours following new files being copied into a UPnP servers folders because most have a scheduled rescan to make sure that new files do get added.

We get asked why we test against MinimServer - UPnP is a great protocol and it can be used for much more than just making music accessible across a network but it is also quite a “loosely defined” protocol and as such there’s a lot of opportunity for interpretation of the standard. MinimServer has been available for many years and has a pretty well proven track record for being a stable and reliable UPnP server that ideal for audio use (it doesn’t try to handle videos or photos or have random hacked-in addons) so that’s why we use MinimServer as our yardstick.

Other UPnP servers should be absolutely fine to use but that “loosely defined” UPnP protocol can mean that there are oddities or differences in browsing and of course each UPnP server has it’s own set of browsing options and functionality - we often get asked by new customers where a specific UPnP browsing option is because they get that option when they are at their friends or when they had their demo at their dealers but they don’t get the same options on their own system at home…



Hi @Phil, I, too, had never heard of MinimServer - I generally stream via either Roon or Mosaic, depending upon mood (have yet to work out which I prefer). However, I have noticed that when I try to access downloaded music that I keep, very simply, on a USB stick in the rear port of my Apex Bartók HDAC, Mosaic often reads the tracks out of order - typically the last three or four tracks play, sequentially, between Tracks 1 & 2. Is this an example of the same issue??


No … when you access files on USB sticks then they are read as folders would be read on a computer and therefore are played in the order that they appear in a file listing in the folder (usually alphabetical) … none of the actual metadata that the files contain is used in determining the play order.

This is why UPnP is recommended as UPnP servers will use the file tagging data when sorting and searching music and give you a far better browsing / searching / sorting experience.


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This is a topic where the licensed version of MinimServer has the advantage of allowing users to amend (configure) browsing properties .

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Hi Pete,

Yes, it’s quite surprising though how few people actually do set-up / configure / modify their UPnP servers beyond the absolute basics of pointing them at a folder full of files.

Even the fundamentals of audio file tagging and how the file tags affect how the music is indexed is very poorly understood on the whole - going as far as the differences between the physical folder and file names when viewed from a PC and the file tags.

I have a friend who contacts me every so often to tell me that he’s been doing some tag editing on his collection and “Can you do your thing so that I can see them…?” when what he actually means is “I’ve changed a load of folder and file names from my computer - can you log in to my PC remotely and run MP3Tag and update the file tags from the updated folder and file names that I’ve changed…” :smiley:


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I agree. However for classical music enthusiasts like me although the capabilities of the ID3 ( used in MP3 editor) metadata format is fine and is far more comprehensive than commonly known, an elephant in the room remains where media players are concerned (including Mosaic). It seems that whoever designed these things was only aware of popular music genres as they typically only function at Album title, Artist Name and tTrack Title levels. For classical music you really need a composer field and ideally a work field too. Yes, ID3 has this metadata intact ( usually) but it is not transferred to the player.

I cannot imagine the number of hours that I have had to spend devising work arounds to give me something that is more or less usable.

Too late now to do anything about it I guess.

Hi Pete,

Track tags do have “composer”, “artist” and “album artist” fields along with “conductor”, “involved people”, “movement name”, “movement” etc. and whether you can browse by those fields is down to the UPnP server NOT the UPnP client.

The UPnP client can only use data that is exposed by the UPnP server but if the UPnP server exposes those fields then there is absolutely no reason why you wouldn’t be able to browse and search on those tags…

Thanks Phil. I am trying to be brief on this as it has moved too far OT

.I understand what you are saying but it does not address the issue with classical music. it is not a search problem but a display one. Without the composer and/or work appearing in the display one cannot tell which composer is responsible for which track ( essential to identify the music) nor if there is any relationship between tracks ( essential to distinguish works which may consist of numerous tracks).

It is also not only a UPnP issue but one that affects all sources.

I think you’re spot on Pete. It is OT and it is important. I have logged a feature request here.

Please can everyone with an interest in better support for the display of classical metadata up-vote it.


Please index. I had this problem and easy fix is reindexing will solve.

Actually it’s called “Rescan” your storage path in Roon. Settings > Storage > (file path 3 dots menu) > Force rescan

You don’t have to do such rescans if the file path is local to the Roon server application as in that case the operating system can notify users of such file path if there are modifications; but in case of a remote file path this signalling is not possible.

Actually even for remote network folder paths, Roon will watch the network folders for changes, and will incorporate new albums into the database automatically.

My Roon Server watches over both my Melco and my Synology NAS for any file additions and automatically adds albums into its database when I load new files on either of them. There’s no need for any manual rescan.

True; but that’s not event-driven but on a timer - one of the settings for a storage location is the “Automatic rescan interval”. By default 4 hours I think; I’ve actually set it to 2 hours. So every 2 hours Roon will do a rescan of the storage location. But Roon does not get notified immediately on changes in a remote network path contrary to a local file system. There is no mechanism for that.

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