A drive the server can't read

When a folder or drive can't be read, its source in Settings says so.

macOS

A background service can't be asked for permission to read an external drive or a protected folder (Desktop, Documents, Pictures), so grant it once:

1. System Settings › Privacy & Security › Full Disk Access.
2. Add the node the service runs. The installer prints its exact path.
3. Restart the service: launchctl kickstart -k gui/$(id -u)/com.diune.media-server.

A Node.js upgrade installs a new node: grant it again.

Linux

The service's user must be able to read the folder. A drive mounted by the desktop under /media/<user>/ is there only while that user is logged in. For a drive that serves the house, mount it in /etc/fstab by its UUID=.

A network share

Network shares (SMB, NFS) can't be sources yet. See Folders and drives.