Are you using a Mac or PC?

If you are using a Windows laptop, this might help: https://support.sonos.com/s/article/813?language=en_US

You will also need to enable SMB(v1)/CIFS support on the Laptop.

Personally, I prefer to store my music on a NAS drive. A computer is not required if the music is stored on a NAS. Replacing or powering down a computer would be a non event.

Windows 10 PC. A new Dell with McAfee Live Safe on it

Is the Sonos desktop controller installed? It also installs an HTTP service for Sonos to access the stored files, obviating the SMB requirement.