Snap Permissions
If you get an error message while trying to import your music from an external HDD/device, then you likely need to enable this permission. To do so, locate Tauon Music Box in the Software Center, and click Permissions:
Then, make sure the setting "Read/write files on removable storage devices" is enabled:
Details: This settings extends access to
/media. If you need access to other mounted locations, this may not be possible with Snap. Consider installing from Flathub as Flatpak has more robust access control.