Metadata of MP3 files can´t be deleted

Core Machine (Operating system/System info/Roon build number)

Core Machine:
Roon Nucleus (version 1.8, build 783)

Network Details (Including networking gear model/manufacturer and if on WiFi/Ethernet)

AVM Fritz!Box 7530, Ethernet

Audio Devices (Specify what device you’re using and its connection type - USB/HDMI/etc.)

  • ProJect Stream Box S2 Ultra > Ethernet to AVM Fritz!Box 7530 > USB output to Nubert loudspeakers with builtin DAC
  • Naim Uniti Core (as a NAS) > Ethernet to AVM Fritz!Box 7530
  • Nubert nuPro X 8000 RC (digital input via USB from Pro-Ject Stream Box)

Description Of Issue

Everything worked fine, till I transferred some MP3 files via the USB port of the Naim Uniti Core.

Roon showed them correctly, but since I deleted them on the Uniti Core (because I don´t like them), I´m not able to delete them in Roon; the metadata with CD cover is still shown as if the files are still on the NAS (but they don´t are, of course). Some files are shown without cover, but the tag „_.trashes - 501“ and „Unknown Artist“ (see attached screenshot).

The function “Wartung der Bibliothek” failed; there are no related files indicated.
Unfortunately I don’t made a current backup before importing and deleting the MP3 files.

I would be very glad if someone can show me a solution.
Thanks a lot for your answer in advance.

Kind regards,


Welcome Frank
I am not familiar with the Uniti Core, but have you emptied the trash can (or it’s equivalent) on the Uniti Core?
To me, it appears that the tracks are in the trash can ("_.trashes"), where Roon still accesses them but doesn’t read them correctly as permissions and file access is modified in trash.
Once you do empty the trash, Go to Roon Settings - Library - click on Clean up Library. You may first also need to go to Settings - Storage - via 3 dots, select Force Rescan

I hope this helps


Hello Ralph,

thanks a lot for your prompt answer!

Unfortunately the Naim support says, that the „Uniti Core“ doesn’t have a trash can (the former „UnitiServe“ did).
It´s weird, that there are no files indicated in the „Clean up Library“ section.

Best regards,

I suspect that while the files themselves have been deleted, the folder (= the “Album”) has just been renamed to something that means “deleted” to the Uniti Core, but which is still seen by Roon.

Can you use a Windows File Explorer or the Mac Finder to browse the music storage of the Uniti Core over the network? If you can find this folder using this method, you may be able to delete it.

Hi Frank,

I would recommend rebooting the Nucleus, this will force it to perform a new scan of shared folders on the Naim Uniti.

Once performed, check your library and also look at library maintenance - clean up, it should list a count of deleted tracks that will approximate to the number of tracks you have recently removed.

Hi @Frank_Fuhrer

Is there any change after a reboot of the Nucleus?

If you click the album to open it up, does it show tracks here? Can you share some more screenshots?

Hello Geoff, Carl and Dylan

thanks a lot for your replies!

I already browsed the file folders of the “Uniti Core“ by the MacOS Finder; there are no remains or the like of the deleted files visible.
My former Naim „UnitiServe” had a folder called „trash can“, but the Naim support assured me, that the "Uniti Core“ doesn’t have this any more.
If I click a deleted album in Roon to open it up, it shows tracks, but of course can´t play them.

Furthermore I made a lot of changes in Roon as to the CD artwork; what will happen with them if I reboot the Nucleus? Of course I have a backup, but this was generated after the problem with the deleted files occurred, so I´m afraid the situation will be the same, when I restore my changes of the metadata from the backup.
Or am I under a misapprehension? Sorry for asking this, but Roon is still new and unfamiliar to me – nevertheless a wonderful system.

Kind regards,

All your changes are stored in the Roon Database, that’s why is vital to have backups in the event that something bad happens.

When the Nucleus reboots, it will start the Roon Core software which will in turn re-load the Roon database stored on the internal SSD.

Then it will rescan the watched filesystems in your case the Naim UnitiServe, this is to cross check the database references against the filesystem files themselves to see if anything has changed.

It’s quite safe to reboot the Nucleus, either via its web interface or just pressing the power button on the case. If there is a issue on restart then the problem has already happened and the reboot is identifying … in which case it’s better to know now that in x months time.