As mjw correctly mentioned above, Roon does not support .iso files. An ISO file is actually a complete disk image archive, not a standalone audio file. Roon’s library management is designed to scan for and play individual music tracks, so it cannot mount or read inside virtual disk images.
To get this music into your Roon library, you will need to extract the files. Here is what you should do:
Mount the ISO file on your computer or use an archive extraction tool to unpack it.
Locate the individual supported audio files (such as FLAC, WAV, DSF, etc.) inside the extracted folder.
Copy those specific music files directly into the storage folder that Roon is currently watching.
Once the actual audio files are placed in your watched folder, Roon will scan and import them without any issues. Please let us know if you have any questions!
Just checking in on this, have you had a chance to unpack the ISO and copy the actual audio files, like FLAC, WAV, or DSF, into the folder your Roon Server is watching? Once those files are in place, Roon should scan them normally, so let us know if you ran into anything along the way, thanks.